Special elections to the United States Senate are held to fill the vacancies that occur when a senator dies or resigns before the completion of their six-year term. Winners of these special elections typically serve the remainder of the term of the senator who has caused the vacancy. General elections to the U.S. Congress are held in November of even-numbered years. New Congresses convened on March 4 of the following year until 1934, and since then, new Congresses have begun on January 3 of the following year.
Because of the cost of conducting a special election,[1] most states hold elections to fill a Senate vacancy in conjunction with the next general election, while some states, such as Alabama[2] and Texas, allow for special elections to the Senate to be held before a general election (similar to special elections to the U.S. House of Representatives, though special elections are on a state-wide basis). Special elections can alter the balance of power in the Senate,[3] as can temporary appointments.
Prior to ratification of the Seventeenth Amendment to the United States Constitution in 1913, most state legislatures elected senators (Sen.), as well as replacement senators. Some states empowered their governor to make temporary appointments until the legislature was in session.
The Seventeenth Amendment now requires the governor (Gov.) of the state to issue a writ for a special election to fill a vacant Senate seat, but no timeframe is specified in the provision for when the special election is to be held. State legislatures may also empower the governor to fill a vacancy by a temporary appointment until the winner of the special election is certified. The constitution does not set out how the temporary appointee is to be selected (e.g., there is no federal requirement that the appointee be of the same party, as happened most recently in New Jersey in 2013), and the state legislature can legislate as to how the replacement is to be selected.
North Dakota, Oregon and Wisconsin do not empower their governor to make temporary appointments and require special elections.[4] [5] Between 2004 and 2008, Massachusetts denied the power of the governor to appoint a replacement; in 2004, the Democratic-controlled legislature wanted to limit the power of the Republican governor (Gov. Mitt Romney) to appoint a successor to then-senator John Kerry if he were elected president that year. With the death of Sen. Ted Kennedy, the legislature chose to revert the rules to allow the Democratic governor (Gov. Deval Patrick) to appoint a temporary replacement senator while awaiting the results of a special election to complete the existing term. Hawaii allows the governor to appoint an interim senator "who serves until the next regularly-scheduled general election, chosen from a list of three prospective appointees that the prior incumbent's political party submits". Alaska in 2004 enacted conflicting legislation and a separate ballot referendum law that took effect on the same day. It is uncertain if the Alaska governor may successfully appoint an interim senator to serve until the mandated special election occurs 60 to 90 days after the vacancy happens. The ballot-approved law fails to specifically authorize the governor to appoint, though the legislative law does.[5] Since 2021, Oklahoma permits its governor again to appoint a successor who is of the same party as the previous senator for at least the preceding five years when the vacancy arises in an even-numbered year, only after the appointee has taken an oath not to run in either a regular or special Senate election.[6]
This is an incomplete list of special elections to the United States Senate. The list only includes vacancies that were filled by special election. Not included are those situations in which vacancies were only filled by appointment or general election, or new seats.
| State (Class) | Original | Appointee | Election winner | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Senator | data-sort-type=date | Vacancy event | Senator | data-sort-type=date | Date | Senator | data-sort-type=date | Date | |||
| Virginia (Class 1) | data-sort-value="Grayson William" | William Grayson (AA) | data-sort-value="March 12, 1790" | Died March 12, 1790 | data-sort-value="Walker John" | John Walker (PA) | data-sort-value="March 31, 1790" | March 31, 1790 | data-sort-value="Monroe James" | James Monroe (AA) | November 9, 1790 |
| New Jersey (Class 2) | data-sort-value="Paterson William" | William Paterson (PA) | data-sort-value="November 13, 1790" | Resigned November 13, 1790 | No appointment | data-sort-value="Dickinson Philemon" | Philemon Dickinson (PA) | November 23, 1790 | |||
| Connecticut (Class 3) | data-sort-value="Johnson William S." | William S. Johnson (PA) | data-sort-value="March 4, 1791" | Resigned March 4, 1791 | No appointment | data-sort-value="Sherman Roger" | Roger Sherman (PA) | June 13, 1791 | |||
| Virginia (Class 2) | data-sort-value="Lee Richard Henry" | Richard Henry Lee (AA) | data-sort-value="October 8, 1792" | Resigned October 8, 1792 | No appointment | data-sort-value="Taylor John" | John Taylor (AA) | October 18, 1792 | |||
| Maryland (Class 1) | data-sort-value="Carroll Charles" | Charles Carroll (PA) | data-sort-value="November 30, 1792" | Resigned November 30, 1792 | No appointment | data-sort-value="Potts Richard" | Richard Potts (PA) | January 10, 1793 | |||
| Pennsylvania (Class 1) | data-sort-value=0 | Vacant | data-sort-value="March 4, 1791" | Failure to elect by March 4, 1791 | No appointment | data-sort-value="Gallatin Albert" | Albert Gallatin (AA) | February 28, 1793 | |||
| Connecticut (Class 3) | data-sort-value="Sherman Roger" | Roger Sherman (PA) | data-sort-value="July 23, 1793" | Died July 23, 1793 | No appointment | data-sort-value="Mitchell Stephen" | Stephen Mitchell (PA) | December 2, 1793 | |||
| New York (Class 3) | data-sort-value="King Rufus" | Rufus King (F) | data-sort-value="May 23, 1796" | Resigned May 23, 1796 | No appointment | data-sort-value="Laurance John" | John Laurance (F) | November 9, 1796 | |||
| New York (Class 1) | data-sort-value="Schuyler Philip" | Philip Schuyler (F) | data-sort-value="January 3, 1798" | Resigned January 3, 1798 | No appointment | data-sort-value="Hobart John Sloss" | John Sloss Hobart (F) | January 11, 1798 | |||
| New York (Class 1) | data-sort-value="Hobart John Sloss" | John Sloss Hobart (F) | data-sort-value="April 16, 1798" | Resigned April 16, 1798 | data-sort-value="North William" | William North (F) | data-sort-value="May 5, 1798" | May 5, 1798 | data-sort-value="Watson James" | James Watson (F) | August 17, 1798 |
| New York (Class 1) | data-sort-value="Watson James" | James Watson (F) | data-sort-value="March 19, 1800" | Resigned March 19, 1800 | No appointment | data-sort-value="Morris Gouverneur" | Gouverneur Morris (F) | April 3, 1800 | |||
| New York (Class 3) | data-sort-value="Laurance John" | John Laurance (F) | data-sort-value="August 1, 1800" | Resigned August 1800 | No appointment | data-sort-value="Armstrong John Jr." | John Armstrong Jr. (DR) | November 6, 1800 | |||
| New York (Class 3) | data-sort-value="Armstrong John Jr." | John Armstrong Jr. (DR) | data-sort-value="February 5, 1802" | Resigned February 5, 1802 | No appointment | data-sort-value="Clinton DeWitt" | DeWitt Clinton (DR) | February 9, 1802 | |||
| New York (Class 1) | data-sort-value="Bailey Theodorus" | Theodorus Bailey (DR) | data-sort-value="January 16, 1804" | Resigned January 16, 1804 | No appointment | data-sort-value="Armstrong John Jr." | John Armstrong Jr. (DR) | February 3, 1804 | |||
| New York (Class 3) | data-sort-value="Armstrong John Jr." | John Armstrong Jr. (DR) | data-sort-value="February 23, 1804" | Resigned February 23, 1804 | No appointment | data-sort-value="Smith John" | John Smith (DR) | ||||
| New York (Class 1) | data-sort-value="Armstrong John Jr." | John Armstrong Jr. (DR) | data-sort-value="June 30, 1804" | Resigned June 30, 1804 | No appointment | data-sort-value="Mitchill Samuel L." | Samuel L. Mitchill (DR) | November 9, 1804 | |||
| Alabama (Class 3) | data-sort-value="Walker John Williams" | John Williams Walker (DR) | data-sort-value="December 12, 1822" | Resigned December 12, 1822 | No appointment | data-sort-value="Kelly William" | William Kelly (DR) | December 12, 1822 | |||
| Delaware (Class 2) | data-sort-value="Van Dyke Nicholas" | Nicholas Van Dyke (F) | data-sort-value="March 4, 1823" | Failure to elect by March 4, 1823 | No appointment | data-sort-value="Van Dyke Nicholas" | Nicholas Van Dyke (F) | January 8, 1824 | |||
| Delaware (Class 1) | data-sort-value="Rodney Caesar A." | Caesar A. Rodney (DR) | data-sort-value="January 29, 1823" | Resigned January 29, 1823 | No appointment | data-sort-value="Clayton Thomas" | Thomas Clayton (F) | ||||
| Louisiana (Class 3) | data-sort-value="Brown James" | James Brown (DR) | data-sort-value="December 10, 1823" | Resigned December 10, 1823 | No appointment | data-sort-value="Johnston Josiah S." | Josiah S. Johnston (DR) | January 15, 1824 | |||
| Louisiana (Class 2) | data-sort-value="Johnson Henry" | Henry Johnson (DR) | data-sort-value="May 27, 1824" | Resigned May 27, 1824 | No appointment | data-sort-value="Bouligny Charles" | Charles Bouligny (DR) | November 19, 1824 | |||
| Illinois (Class 3) | data-sort-value="Edwards Ninian" | Ninian Edwards (DR) | data-sort-value="March 4, 1824" | Resigned March 4, 1824 | No appointment | data-sort-value="McLean John" | John McLean (DR) | November 24, 1824 | |||
| Georgia (Class 2) | data-sort-value="Ware Nicholas" | Nicholas Ware (DR) | data-sort-value="January 29, 1823" | Died January 29, 1823 | No appointment | data-sort-value="Cobb Thomas W." | Thomas W. Cobb (F) | December 6, 1824 | |||
| Virginia (Class 2) | data-sort-value="Taylor John" | John Taylor (DR) | data-sort-value="August 21, 1824" | Died August 21, 1824 | No appointment | data-sort-value="Tazewell Littleton" | Littleton Tazewell (DR) | December 7, 1824 | |||
| Alabama (Class 3) | data-sort-value="Chambers Henry H." | Henry H. Chambers (DR) | data-sort-value="January 24, 1826" | Died January 24, 1826 | data-sort-value="Pickens Israel" | Israel Pickens (DR) | data-sort-value="February 17, 1826" | February 17, 1826 | data-sort-value="McKinley John" | John McKinley (J) | November 27, 1826 |
| New York (Class 1) | data-sort-value="Van Buren Martin" | Martin Van Buren (DR) | data-sort-value="December 20, 1828" | Resigned December 20, 1828 | No appointment | data-sort-value="Dudley Charles E." | Charles E. Dudley (D) | January 15, 1829 | |||
| New York (Class 3) | data-sort-value="Marcy William L." | William L. Marcy (D) | data-sort-value="January 1, 1833" | Resigned January 1, 1833 | No appointment | data-sort-value="Wright Silas" | Silas Wright (D) | January 4, 1833 | |||
| Alabama (Class 3) | data-sort-value="McKinley John" | John McKinley (D) | data-sort-value="April 22, 1837" | Resigned April 22, 1837 | data-sort-value="Clay Clement Comer" | Clement Comer Clay (D) | data-sort-value="June 19, 1837" | June 19, 1837 | data-sort-value="Bagby Arthur P." | Arthur P. Bagby (D) | November 24, 1841 |
| Arkansas (Class 2) | data-sort-value="Fulton William S." | William S. Fulton (D) | data-sort-value="August 15, 1844" | Died August 15, 1844 | No appointment | data-sort-value="Ashley Chester" | Chester Ashley (D) | November 8, 1844 | |||
| New York (Class 1) | data-sort-value="Tallmadge Nathaniel P." | Nathaniel P. Tallmadge (W) | data-sort-value="June 17, 1844" | Resigned June 17, 1844 | data-sort-value="Dickinson Daniel S." | Daniel S. Dickinson (D) | data-sort-value="November 30, 1844" | November 30, 1844 | data-sort-value="Dickinson Daniel S." | Daniel S. Dickinson (D) | January 18, 1845 |
| New York (Class 3) | data-sort-value="Wright Silas" | Silas Wright (D) | data-sort-value="November 26, 1844" | Resigned November 26, 1844 | data-sort-value="Foster Henry A." | Henry A. Foster (D) | data-sort-value="November 30, 1844" | November 30, 1844 | data-sort-value="Dix John Adams" | John Adams Dix (D) | January 18, 1845 |
| Arkansas (Class 2) | data-sort-value="Ashley Chester" | Chester Ashley (D) | data-sort-value="April 29, 1848" | Died April 29, 1848 | data-sort-value="Sebastian William K." | William K. Sebastian (D) | data-sort-value="May 12, 1848" | May 12, 1848 | data-sort-value="Sebastian William K." | William K. Sebastian (D) | November 17, 1848 |
| Alabama (Class 2) | data-sort-value="Lewis Dixon Hall" | Dixon Hall Lewis (D) | data-sort-value="October 24, 1848" | Died October 24, 1848 | data-sort-value="Fitzpatrick Benjamin" | Benjamin Fitzpatrick (D) | data-sort-value="November 25, 1848" | November 25, 1848 | data-sort-value="Clemens Jeremiah" | Jeremiah Clemens (D) | November 30, 1849 |
| Massachusetts (Class 2) | data-sort-value="Webster Daniel" | Daniel Webster (W) | data-sort-value="July 22, 1850" | Resigned July 22, 1850 | data-sort-value="Winthrop Robert Charles" | Robert Charles Winthrop (W) | data-sort-value="July 30, 1850" | July 30, 1850 | data-sort-value="Rantoul Jr. Robert" | Robert Rantoul Jr. (D) | January 14, 1851 |
| New Hampshire (Class 3) | data-sort-value="Bell James" | James Bell (R) | data-sort-value="May 26, 1857" | Died May 26, 1857 | No appointment | data-sort-value="Clark Daniel" | Daniel Clark (R) | June 26, 1857 | |||
| Tennessee (Class 1) | data-sort-value=0 | Vacant | data-sort-value="March 4, 1857" | Failure to elect by March 4, 1857 | No appointment | data-sort-value="Johnson Andrew" | Andrew Johnson (D) | October 8, 1857 | |||
| South Carolina (Class 3) | data-sort-value="Butler Andrew" | Andrew Butler | data-sort-value="May 25, 1857" | Died May 25, 1857 | No appointment | data-sort-value="Hammond James Henry" | James Henry Hammond (D) | December 6, 1857 | |||
| North Carolina (Class 3) | data-sort-value="Biggs Asa" | Asa Biggs | data-sort-value="May 5, 1858" | Resigned May 5, 1858 | data-sort-value="Clingman Thomas Lanier" | Thomas Lanier Clingman (D) | data-sort-value="May 7, 1858" | May 7, 1858 | data-sort-value="Clingman Thomas Lanier" | Thomas Lanier Clingman (D) | November 23, 1858 |
| California (Class 3) | data-sort-value="Broderick David C." | David C. Broderick (D) | data-sort-value="September 16, 1859" | Died September 16, 1859 | data-sort-value="Haun Henry P." | Henry P. Haun (D) | data-sort-value="November 3, 1859" | November 3, 1859 | data-sort-value="Latham Milton S." | Milton S. Latham (D) | January 11, 1860 |
| California (Class 1) | data-sort-value="Casserly Eugene" | Eugene Casserly (D) | data-sort-value="November 29, 1873" | Resigned November 29, 1873 | No appointment | data-sort-value="Hager John S." | John S. Hager (D) | December 23, 1873 | |||
| Alabama (Class 3) | data-sort-value="Houston George S." | George S. Houston (D) | data-sort-value="December 31, 1879" | Died December 31, 1879 | data-sort-value="Pryor Luke" | Luke Pryor (D) | data-sort-value="January 7, 1880" | January 7, 1880 | data-sort-value="Pugh James L." | James L. Pugh (D) | November 24, 1880 |
| New York (Class 1) | data-sort-value="Platt Thomas C." | Thomas C. Platt (R) | data-sort-value="May 16, 1881" | Resigned May 16, 1881 | No appointment | data-sort-value="Miller Warner" | Warner Miller (R) | July 16, 1881 | |||
| New York (Class 3) | data-sort-value="Conkling Roscoe" | Roscoe Conkling (R) | data-sort-value="May 16, 1881" | Resigned May 16, 1881 | No appointment | data-sort-value="Lapham Elbridge G." | Elbridge G. Lapham (R) | July 22, 1881 | |||
| Arkansas (Class 2) | data-sort-value="Garland Augustus" | Augustus Garland (D) | data-sort-value="March 6, 1885" | Resigned March 6, 1885 | No appointment | data-sort-value="Berry James H." | James H. Berry (D) | March 20, 1885 | |||
| California (Class 1) | data-sort-value="Miller John Franklin" | John Franklin Miller (R) | data-sort-value="March 8, 1886" | Died March 8, 1886 | data-sort-value="Hearst George" | George Hearst (D) | data-sort-value="March 23, 1886" | March 23, 1886 | data-sort-value="Williams Abram P." | Abram P. Williams (R) | August 4, 1886 |
| California (Class 1) | data-sort-value="Hearst George" | George Hearst (D) | data-sort-value="February 28, 1891" | Died February 28, 1891 | No appointment | data-sort-value="Felton Charles N." | Charles N. Felton (R) | March 19, 1891 | |||
| California (Class 3) | data-sort-value="Stanford Leland" | Leland Stanford (R) | data-sort-value="June 21, 1893" | Died June 21, 1893 | data-sort-value="Perkins George C." | George C. Perkins (R) | data-sort-value="July 26, 1893" | July 26, 1893 | data-sort-value="Perkins George C." | George C. Perkins (R) | January 22, 1895 |
| Mississippi (Class 2) | data-sort-value="Walthall Edward C." | Edward C. Walthall (D) | data-sort-value="January 24, 1894" | Resigned January 24, 1894 | No appointment | data-sort-value="McLaurin Anselm J." | Anselm J. McLaurin (D) | February 7, 1894 | |||
| Louisiana (Class 3) | data-sort-value="White Edward D." | Edward D. White (D) | data-sort-value="March 12, 1894" | Resigned March 12, 1894 | data-sort-value="Blanchard Newton C." | Newton C. Blanchard (D) | data-sort-value="March 12, 1894" | March 12, 1894 | data-sort-value="Blanchard Newton C." | Newton C. Blanchard (D) | May 16, 1894 |
| Georgia (Class 2) | data-sort-value="Colquitt Alfred H." | Alfred H. Colquitt (D) | data-sort-value="March 26, 1894" | Died March 26, 1894 | data-sort-value="Walsh Patrick" | Patrick Walsh (D) | data-sort-value="April 2, 1894" | April 2, 1894 | data-sort-value="Walsh Patrick" | Patrick Walsh (D) | November 2, 1894 |
| North Carolina (Class 3) | data-sort-value="Vance Zebulon B." | Zebulon B. Vance | data-sort-value="April 14, 1894" | Died April 14, 1894 | data-sort-value="Jarvis Thomas J." | Thomas J. Jarvis (D) | data-sort-value="April 19, 1894" | April 19, 1894 | data-sort-value="Pritchard Jeter C." | Jeter C. Pritchard (D) | January 23, 1895 |
| Michigan (Class 1) | data-sort-value="Stockbridge Francis B." | Francis B. Stockbridge (R) | data-sort-value="April 3, 1894" | Died April 3, 1894 | data-sort-value="Patton John Jr." | John Patton Jr. (R) | data-sort-value="May 5, 1894" | May 5, 1894 | data-sort-value="Burrows Julius C." | Julius C. Burrows (R) | January 24, 1895 |
| Montana (Class 1) | data-sort-value=0 | Vacant | data-sort-value="March 4, 1893" | Failure to elect by March 4, 1893 | No appointment | data-sort-value="Mantle Lee" | Lee Mantle (R) | January 16, 1895 | |||
| Wyoming (Class 1) | data-sort-value=0 | Vacant | data-sort-value="March 4, 1893" | Failure to elect by March 4, 1893 | No appointment | data-sort-value="Clark Clarence D." | Clarence D. Clark (R) | January 23, 1895 | |||
| Washington (Class 1) | data-sort-value=0 | Vacant | data-sort-value="March 4, 1893" | Failure to elect by March 4, 1893 | No appointment | data-sort-value="Wilson John L." | John L. Wilson (R) | February 19, 1895 | |||
| Mississippi (Class 2) | data-sort-value="Walthall Edward C." | Edward C. Walthall (D) | data-sort-value="April 21, 1898" | Died April 21, 1898 | data-sort-value="Sullivan William V." | William V. Sullivan (D) | data-sort-value="May 31, 1898" | May 31, 1898 | data-sort-value="Sullivan William V." | William V. Sullivan (D) | January 16, 1900 |
| Alabama (Class 3) | data-sort-value="Pettus Edmund" | Edmund Pettus (D) | data-sort-value="July 27, 1907" | Died July 27, 1907 | No appointment | data-sort-value="Johnston Joseph F." | Joseph F. Johnston (D) | August 6, 1907 | |||
| Pennsylvania (Class 1) | data-sort-value="Knox Philander C." | Philander C. Knox (R) | data-sort-value="March 4, 1909" | Resigned March 4, 1909 | No appointment | data-sort-value="Oliver George T." | George T. Oliver (R) | March 17, 1909 | |||
| Mississippi (Class 2) | data-sort-value="McLaurin Anselm J." | Anselm J. McLaurin (D) | data-sort-value="December 22, 1909" | Died December 22, 1909 | data-sort-value="Gordon James" | James Gordon (D) | data-sort-value="December 27, 1909" | December 27, 1909 | data-sort-value="Percy LeRoy" | LeRoy Percy (D) | February 22, 1910 |
| Louisiana (Class 3) | data-sort-value="McEnery Samuel D." | Samuel D. McEnery (D) | data-sort-value="June 28, 1910" | Died June 28, 1910 | data-sort-value="Thornton John" | John Thornton (D) | data-sort-value="August 27, 1910" | August 27, 1910 | data-sort-value="Thornton John" | John Thornton (D) | December 6, 1910 |
| North Dakota (Class 3) | Martin N. Johnson (R) | Died October 12, 1909 | data-sort-value="Thompson Fountain L." | Fountain L. Thompson (D) | data-sort-value="November 10, 1909" | November 10, 1909 – Jan. 31, 1910 (resigned) | Asle Gronna (R) | February 1, 1911 | |||
| data-sort-value="Purcell William E." | William E. Purcell (D) | data-sort-value="February 1, 1910" | February 1, 1910 | ||||||||
| West Virginia (Class 2) | data-sort-value="Elkins Stephen Benton" | Stephen Benton Elkins (R) | data-sort-value="January 4, 1911" | Died January 4, 1911 | data-sort-value="Elkins Davis" | Davis Elkins (R) | data-sort-value="January 9, 1911" | January 9, 1911 | data-sort-value="Watson Clarence Wayland" | Clarence Wayland Watson (D) | February 1, 1911 |
| Iowa (Class 3) | data-sort-value="Dolliver Jonathan P." | Jonathan P. Dolliver (R) | data-sort-value="October 15, 1910" | Died October 15, 1910 | data-sort-value="Young Lafayette" | Lafayette Young (R) | data-sort-value="November 4, 1910" | November 4, 1910 | data-sort-value="Kenyon William S." | William S. Kenyon (R) | April 11, 1911 |
| Georgia (Class 3) | data-sort-value="Clay Alexander S." | Alexander S. Clay (D) | data-sort-value="November 13, 1910" | Died November 13, 1910 | data-sort-value="Terrell Joseph M." | Joseph M. Terrell (D) | data-sort-value="November 17, 1910" | November 17, 1910 | data-sort-value="Smith M. Hoke" | M. Hoke Smith (D) | July 12, 1911 |
| Maine (Class 2) | data-sort-value="Frye William P." | William P. Frye (R) | data-sort-value="August 8, 1911" | Died August 8, 1911 | No appointment | data-sort-value="Gardner Obadiah" | Obadiah Gardner (D) | April 2, 1912 | |||
| Colorado (Class 3) | data-sort-value="Hughes Charles J. Jr." | Charles J. Hughes Jr. (D) | data-sort-value="January 11, 1911" | Died January 11, 1911 | No appointment | data-sort-value="Thomas Charles S." | Charles S. Thomas (D) | January 15, 1913 | |||
| Tennessee (Class 2) | data-sort-value="Taylor Robert Love" | Robert Love Taylor (D) | data-sort-value="March 31, 1912" | Died March 31, 1912 | data-sort-value="Sanders Newell" | Newell Sanders (R) | data-sort-value="April 11, 1912" | April 11, 1912 | data-sort-value="Webb William R." | William R. Webb (D) | January 23, 1913 |
| Nevada (Class 1) | data-sort-value="Nixon George S." | George S. Nixon (R) | data-sort-value="June 5, 1912" | Died June 5, 1912 | data-sort-value="Massey William A." | William A. Massey (R) | data-sort-value="July 1, 1912" | July 1, 1912 | data-sort-value="Pittman Key" | Key Pittman (D) | January 23, 1913 |
| Texas (Class 2) | data-sort-value="Bailey Joseph Weldon" | Joseph Weldon Bailey (D) | data-sort-value="January 3, 1913" | Resigned January 3, 1913 | data-sort-value="Johnston Rienzi Melville" | Rienzi Melville Johnston (D) | data-sort-value="January 4, 1913" | January 4, 1913 | data-sort-value="Sheppard Morris" | Morris Sheppard (D) | January 23, 1913 |
| Arkansas (Class 2) | data-sort-value="Davis Jeff" | Jeff Davis | data-sort-value="January 3, 1913" | Died January 3, 1913 | data-sort-value="Heiskell John N." | John N. Heiskell (D) | data-sort-value="January 6, 1913" | January 6, 1913 | data-sort-value="Kavanaugh William Marmaduke" | William Marmaduke Kavanaugh (D) | January 23, 1913 |
| Idaho (Class 3) | data-sort-value="Heyburn Weldon B." | Weldon B. Heyburn (R) | data-sort-value="October 17, 1912" | Died October 17, 1912 | data-sort-value="Perky Kirtland Irving" | Kirtland Irving Perky (D) | data-sort-value="November 18, 1912" | November 18, 1912 | data-sort-value="Brady James H." | James H. Brady (R) | January 24, 1913 |
| Illinois (Class 3) | data-sort-value="Lorimer William" | William Lorimer (R) | data-sort-value="July 13, 1912" | Election invalidated July 13, 1912 | No appointment | data-sort-value="Sherman Lawrence Yates" | Lawrence Yates Sherman (R) | March 26, 1913 | |||
| Seventeenth Amendment ratified April 8, 1913. All subsequent Senate elections are by popular vote. | |||||||||||
| Maryland (Class 1) | data-sort-value="Rayner Isidor" | Isidor Rayner (D) | data-sort-value="November 25, 1912" | Died November 25, 1912 | data-sort-value="Jackson William P." | William P. Jackson (R) | data-sort-value="November 29, 1912" | November 29, 1912 | data-sort-value="Lee Blair" | Blair Lee (D) | November 4, 1913 |
| Alabama (Class 3) | data-sort-value="Johnston Joseph F." | Joseph F. Johnston (D) | data-sort-value="August 8, 1913" | Died August 8, 1913 | No appointment | data-sort-value="White Francis S." | Francis S. White (D) | May 11, 1914 | |||
| Georgia (Class 2) | data-sort-value="Bacon Augustus Octavius" | Augustus Octavius Bacon (D) | data-sort-value="February 14, 1914" | Died February 14, 1914 | data-sort-value="West William S." | William S. West (D) | data-sort-value="March 1, 1914" | March 1, 1914 | data-sort-value="Hardwick Thomas W." | Thomas W. Hardwick (D) | November 3, 1914 |
| Kentucky (Class 3) | data-sort-value="Bradley William O." | William O. Bradley (R) | data-sort-value="May 23, 1914" | Died May 23, 1914 | data-sort-value="Camden Johnson N." | Johnson N. Camden (D) | data-sort-value="June 16, 1914" | June 16, 1914 | data-sort-value="Camden Johnson N." | Johnson N. Camden (D) | November 3, 1914 |
| Maine (Class 2) | data-sort-value="Burleigh Edwin C." | Edwin C. Burleigh (R) | data-sort-value="June 16, 1916" | Died June 16, 1916 | No appointment | data-sort-value="Fernald Bert M." | Bert M. Fernald (R) | September 11, 1916 | |||
| Indiana (Class 3) | data-sort-value="Shively Benjamin F." | Benjamin F. Shively (D) | data-sort-value="March 14, 1916" | Died March 14, 1916 | data-sort-value="Taggart Thomas" | Thomas Taggart (D) | data-sort-value="March 20, 1916" | March 20, 1916 | data-sort-value="Watson James Eli" | James Eli Watson (R) | November 7, 1916 |
| Arkansas (Class 3) | data-sort-value="Clarke James Paul" | James Paul Clarke (D) | data-sort-value="October 1, 1916" | Died October 1, 1916 | No appointment | data-sort-value="Kirby William F." | William F. Kirby (D) | November 7, 1916 | |||
| Wisconsin (Class 3) | data-sort-value="Husting Paul O." | Paul O. Husting (D) | data-sort-value="October 21, 1917" | Died October 21, 1917 | No appointment | data-sort-value="Lenroot Irvine L." | Irvine L. Lenroot (R) | April 18, 1918 | |||
| Oregon (Class 2) | data-sort-value="Lane Harry" | Harry Lane (D) | data-sort-value="May 23, 1917" | Died May 23, 1917 | data-sort-value="McNary Charles L." | Charles L. McNary (R) | data-sort-value="May 29, 1917" | May 29, 1917 | data-sort-value="Mulkey Frederick W." | Frederick W. Mulkey (R) | November 5, 1918 |
| Nevada (Class 3) | data-sort-value="Newlands Francis G." | Francis G. Newlands (D) | data-sort-value="December 24, 1917" | Died December 24, 1917 | data-sort-value="Henderson Charles B." | Charles B. Henderson (D) | data-sort-value="January 12, 1918" | January 12, 1918 | data-sort-value="Henderson Charles B." | Charles B. Henderson (D) | November 5, 1918 |
| Idaho (Class 3) | data-sort-value="Brady James H." | James H. Brady (R) | data-sort-value="January 13, 1918" | Died January 13, 1918 | data-sort-value="Nugent John F." | John F. Nugent (D) | data-sort-value="January 22, 1918" | January 22, 1918 | data-sort-value="Nugent John F." | John F. Nugent (D) | November 5, 1918 |
| New Jersey (Class 2) | data-sort-value="Hughes William" | William Hughes (D) | data-sort-value="January 30, 1918" | Died January 30, 1918 | data-sort-value="Baird David" | David Baird (R) | data-sort-value="February 23, 1918" | February 23, 1918 | data-sort-value="Baird David" | David Baird (R) | November 5, 1918 |
| Louisiana (Class 3) | data-sort-value="Broussard Robert F." | Robert F. Broussard (D) | data-sort-value="April 12, 1918" | Died April 12, 1918 | data-sort-value="Guion Walter" | Walter Guion (D) | data-sort-value="April 22, 1918" | April 22, 1918 | data-sort-value="Gay Edward" | Edward Gay (D) | November 5, 1918 |
| Missouri (Class 3) | data-sort-value="Stone William J." | William J. Stone (D) | data-sort-value="April 14, 1918" | Died April 14, 1918 | data-sort-value="Wilfley Xenophon P." | Xenophon P. Wilfley (D) | data-sort-value="April 30, 1918" | April 30, 1918 | data-sort-value="Spencer Selden P." | Selden P. Spencer (R) | November 5, 1918 |
| South Carolina (Class 2) | data-sort-value="Tillman Benjamin R." | Benjamin R. Tillman (D) | data-sort-value="July 3, 1918" | Died July 3, 1918 | data-sort-value="Benet Christie" | Christie Benet (D) | data-sort-value="July 6, 1918" | July 6, 1918 | data-sort-value="Pollock William P." | William P. Pollock (D) | November 5, 1918 |
| New Hampshire (Class 3) | data-sort-value="Gallinger Jacob H." | Jacob H. Gallinger (R) | data-sort-value="August 17, 1918" | Died August 17, 1918 | data-sort-value="Drew Irving W." | Irving W. Drew (R) | data-sort-value="September 2, 1918" | September 2, 1918 | data-sort-value="Moses George H." | George H. Moses (R) | November 5, 1918 |
| Virginia (Class 2) | data-sort-value="Martin Thomas S." | Thomas S. Martin (D) | data-sort-value="November 12, 1919" | Died November 12, 1919 | data-sort-value="Glass Carter" | Carter Glass (D) | data-sort-value="November 18, 1919" | November 18, 1919 | data-sort-value="Glass Carter" | Carter Glass (D) | November 2, 1920 |
| Alabama (Class 3) | data-sort-value="Bankhead John H." | John H. Bankhead (D) | data-sort-value="March 1, 1920" | Died March 1, 1920 | data-sort-value="Comer B. B." | B. B. Comer (D) | data-sort-value="March 5, 1920" | March 5, 1920 | data-sort-value="Heflin J. Thomas" | J. Thomas Heflin (D) | November 2, 1920 |
| New Mexico (Class 2) | data-sort-value="Fall Albert B." | Albert B. Fall (R) | data-sort-value="March 3, 1921" | Resigned March 3, 1921 | data-sort-value="Bursum Holm O." | Holm O. Bursum (R) | data-sort-value="March 5, 1920" | March 11, 1921 | data-sort-value="Bursum Holm O." | Holm O. Bursum (D) | September 20, 1921 |
| Delaware (Class 1) | data-sort-value="Wolcott Josiah O." | Josiah O. Wolcott (D) | data-sort-value="July 2, 1921" | Resigned July 2, 1921 | data-sort-value="du Pont T. Coleman" | T. Coleman du Pont (R) | data-sort-value="July 7, 1921" | July 7, 1921 | data-sort-value="Bayard Thomas F. Jr." | Thomas F. Bayard Jr. (D) | November 7, 1922 |
| Pennsylvania (Class 1) | Philander C. Knox (R) | Died October 12, 1921 | data-sort-value="Crow William E." | William E. Crow (R) | data-sort-value="October 17, 1921" | October 17, 1921 – August 2, 1922 (died) | David A. Reed (R) | November 7, 1922 | |||
| data-sort-value="Reed David A." | David A. Reed (R) | data-sort-value="August 8, 1922" | August 8, 1922 | ||||||||
| Pennsylvania (Class 3) | data-sort-value="Penrose Boies" | Boies Penrose (R) | data-sort-value="December 31, 1921" | Died December 31, 1921 | data-sort-value="Pepper George W." | George W. Pepper (R) | data-sort-value="January 9, 1922" | January 9, 1922 | data-sort-value="Pepper George W." | George W. Pepper (R) | November 7, 1922 |
| Iowa (Class 2) | data-sort-value="Kenyon William S." | William S. Kenyon (R) | data-sort-value="February 24, 1922" | Resigned February 24, 1922 | data-sort-value="Rawson Charles A." | Charles A. Rawson (R) | data-sort-value="February 24, 1922" | February 24, 1922 | data-sort-value="Brookhart Smith W." | Smith W. Brookhart (R) | November 7, 1922 |
| Georgia (Class 3) | data-sort-value="Watson Thomas E." | Thomas E. Watson (D) | data-sort-value="September 26, 1922" | Died September 26, 1922 | data-sort-value="Felton Rebecca" | Rebecca Felton (D) | data-sort-value="November 21, 1922" | November 21, 1922 | data-sort-value="George Walter F." | Walter F. George (D) | November 7, 1922 |
| Colorado (Class 2) | data-sort-value="Nicholson Samuel D." | Samuel D. Nicholson (R) | data-sort-value="March 24, 1923" | Died March 24, 1923 | data-sort-value="Adams Alva B." | Alva B. Adams (D) | data-sort-value="May 17, 1923" | May 17, 1923 | data-sort-value="Means Rice W." | Rice W. Means (R) | November 4, 1924 |
| Connecticut (Class 3) | data-sort-value="Brandegee Frank B." | Frank B. Brandegee (R) | data-sort-value="October 14, 1924" | Died October 14, 1924 | No appointment | data-sort-value="Bingham Hiram III" | Hiram Bingham III (R) | December 16, 1924 | |||
| Idaho (Class 3) | data-sort-value="Gooding Frank" | Frank Gooding (R) | data-sort-value="June 24, 1928" | Died June 24, 1928 | data-sort-value="Thomas John" | John Thomas (D) | data-sort-value="June 30, 1928" | June 30, 1928 | data-sort-value="Thomas John" | John Thomas (R) | November 6, 1928 |
| Ohio (Class 3) | data-sort-value="Willis Frank B." | Frank B. Willis (R) | data-sort-value="March 30, 1928" | Died March 30, 1928 | data-sort-value="Locher Cyrus" | Cyrus Locher (D) | data-sort-value="April 5, 1928" | April 5, 1928 | data-sort-value="Burton Theodore E." | Theodore E. Burton (R) | November 6, 1928 |
| Ohio (Class 3) | data-sort-value="Burton Theodore E." | Theodore E. Burton (R) | data-sort-value="October 28, 1929" | Died October 28, 1929 | data-sort-value="McCullouch Roscoe C." | Roscoe C. McCulloch (R) | data-sort-value="November 5, 1929" | November 5, 1929 | data-sort-value="Bulkley Robert J." | Robert J. Bulkley (D) | November 4, 1930 |
| Arkansas (Class 3) | data-sort-value="Caraway Thaddeus H." | Thaddeus H. Caraway (D) | data-sort-value="November 6, 1931" | Died November 6, 1931 | data-sort-value="Caraway Hattie" | Hattie Caraway (D) | data-sort-value="December 9, 1931" | December 9, 1931 | data-sort-value="Caraway Hattie" | Hattie Caraway (D) | January 12, 1932 |
| New Jersey (Class 2) | data-sort-value="Morrow Dwight" | Dwight Morrow (R) | data-sort-value="October 5, 1931" | Died October 5, 1931 | data-sort-value="Barbour William Warren" | William Warren Barbour (R) | data-sort-value="December 1, 1931" | December 1, 1931 | data-sort-value="Barbour William Warren" | William Warren Barbour (R) | November 8, 1932 |
| Georgia (Class 3) | data-sort-value="Harris William J." | William J. Harris (D) | data-sort-value="April 18, 1932" | Died April 18, 1932 | data-sort-value="Cohen John S." | John S. Cohen (D) | data-sort-value="April 25, 1932" | April 25, 1932 | data-sort-value="Russell Richard Jr." | Richard Russell Jr. (D) | November 8, 1932 |
| Vermont (Class 3) | data-sort-value="Dale Porter H." | Porter H. Dale (R) | data-sort-value="October 6, 1933" | Died October 6, 1933 | data-sort-value="Gibson Ernest W." | Ernest W. Gibson (R) | data-sort-value="November 21, 1933" | November 21, 1933 | data-sort-value="Gibson Ernest W." | Ernest W. Gibson (R) | January 16, 1934 |
| Montana (Class 3) | data-sort-value="Walsh Thomas J." | Thomas J. Walsh (D) | data-sort-value="March 4, 1933" | Died March 4, 1933 | data-sort-value="Erickson John E." | John E. Erickson (D) | data-sort-value="March 13, 1933" | March 13, 1933 | data-sort-value="Murray James E." | James E. Murray (D) | November 6, 1934 |
| Tennessee (Class 2) | data-sort-value="Hull Cordell" | Cordell Hull (D) | data-sort-value="March 4, 1933" | Resigned March 4, 1933 | data-sort-value="Bachman Nathan L." | Nathan L. Bachman (D) | data-sort-value="March 4, 1933" | March 4, 1933 | data-sort-value="Bachman Nathan L." | Nathan L. Bachman (D) | November 6, 1934 |
| New Mexico (Class 2) | data-sort-value="Bratton Sam G." | Sam G. Bratton (D) | data-sort-value="June 24, 1933" | Resigned June 24, 1933 | data-sort-value="Hatch Carl A." | Carl A. Hatch (D) | data-sort-value="October 10, 1933" | October 10, 1933 | data-sort-value="Hatch Carl A." | Carl A. Hatch (D) | November 6, 1934 |
| Louisiana (Class 2) | data-sort-value="Long Huey" | Huey Long (D) | data-sort-value="September 10, 1935" | Died September 10, 1935 | data-sort-value="Long Rose McConnell" | Rose Long (D) | data-sort-value="January 31, 1936" | January 31, 1936 | data-sort-value="Long Rose McConnell" | Rose Long (D) | April 21, 1936 |
| Florida(Class 1) | data-sort-value="Trammell" | Park Trammell | Died May 8, 1936 | data-sort-value="Loftin" | Scott Loftin (D) | May 26, 1936 | data-sort-value="Andrews" | Charles O. Andrews (D) | November 3, 1936 | ||
| Florida(Class 3) | data-sort-value="Fletcher" | Duncan U. Fletcher | Died June 17, 1936 | data-sort-value="Hill" | William Luther Hill (D) | July 1, 1936 | data-sort-value="Pepper" | Claude Pepper (D) | November 3, 1936 | ||
| Arkansas (Class 3) | data-sort-value="Robinson Joseph T." | Joseph T. Robinson (D) | data-sort-value="July 14, 1937" | Died July 14, 1937 | No appointment | data-sort-value="Miller John E." | John E. Miller (ID) | November 15, 1937 | |||
| Alabama (Class 3) | Hugo Black (D) | Resigned August 19, 1937 | data-sort-value="Bibb Graves Dixie" | Dixie Graves (D) | data-sort-value="August 20, 1937" | August 20, 1937 – Jan. 10, 1938 (resigned) | Lister Hill (D) | April 26, 1938 | |||
| data-sort-value="Hill J. Lister" | Lister Hill (D) | data-sort-value="January 11, 1938" | January 11, 1938 | ||||||||
| Tennessee (Class 2) | data-sort-value="Bachman Nathan L." | Nathan L. Bachman (D) | data-sort-value="April 23, 1937" | Died April 23, 1937 | data-sort-value="Berry George L." | George L. Berry (D) | data-sort-value="May 6, 1937" | May 6, 1937 | data-sort-value="Stewart Tom" | Tom Stewart (D) | April 26, 1938 |
| New York (Class 1) | data-sort-value="Copeland Royal S." | Royal Copeland (D) | data-sort-value="June 17, 1938" | Died June 17, 1938 | No appointment | data-sort-value="Mead James M." | James M. Mead (D) | November 8, 1938 | |||
| South Dakota (Class 3) | data-sort-value="Hitchcock Herbert E." | Herbert E. Hitchcock (D) | data-sort-value="November 8, 1938" | Resigned November 8, 1938 | No appointment | data-sort-value="Pyle Gladys" | Gladys Pyle (R) | November 9, 1938 | |||
| Texas (Class 2) | data-sort-value="Sheppard Morris" | Morris Sheppard (D) | data-sort-value="April 9, 1941" | Died April 9, 1941 | data-sort-value="Houston Andrew Jackson" | Andrew Houston (D) | data-sort-value="April 21, 1941" | April 21, 1941 | data-sort-value="O'Daniel W. Lee" | W. Lee O'Daniel (D) | June 28, 1941 |
| Mississippi (Class 2) | data-sort-value="Harrison Pat" | Pat Harrison (D) | data-sort-value="June 22, 1941" | Died June 22, 1941 | data-sort-value="Eastland James" | James Eastland (D) | data-sort-value="June 30, 1941" | June 30, 1941 | data-sort-value="Doxey Wall" | Wall Doxey (D) | September 23, 1941 |
| South Carolina (Class 2) | James F. Byrnes (D) | Resigned July 17, 1941 | data-sort-value="Lumpkin Alva M." | Alva Lumpkin (D) | data-sort-value="July 22, 1941" | July 22, 1941 – August 1, 1941 (died) | Burnet Maybank (D) | November 5, 1941 | |||
| data-sort-value="Peace Roger C." | Roger Peace (D) | data-sort-value="August 5, 1941" | August 5, 1941 | ||||||||
| Colorado (Class 3) | data-sort-value="Adams Alva B." | Alva B. Adams (D) | data-sort-value="December 1, 1941" | Died December 1, 1941 | data-sort-value="Millikin Eugene" | Eugene Millikin (R) | data-sort-value="December 20, 1941" | December 20, 1941 | data-sort-value="Millikin Eugene" | Eugene Millikin (R) | November 3, 1942 |
| West Virginia (Class 2) | data-sort-value="Neely Matthew M." | Matthew M. Neely (D) | data-sort-value="January 12, 1941" | Resigned January 12, 1941 | data-sort-value="Rosier Joseph" | Joseph Rosier (D) | data-sort-value="January 13, 1941" | January 13, 1941 | data-sort-value="Shott Hugh Ike" | Hugh Ike Shott (R) | November 3, 1942 |
| Nevada (Class 1) | data-sort-value="Pittman Key" | Key Pittman (D) | data-sort-value="November 10, 1940" | Died November 10, 1940 | data-sort-value="Bunker Berkeley" | Berkeley Bunker (D) | data-sort-value="November 27, 1940" | November 27, 1940 | data-sort-value="Scrugham James G." | James G. Scrugham (D) | November 3, 1942 |
| Indiana (Class 3) | data-sort-value="Van Nuys Frederick" | Frederick Van Nuys (D) | data-sort-value="January 25, 1944" | Died January 25, 1944 | data-sort-value="Jackson Samuel D." | Samuel D. Jackson (D) | data-sort-value="January 28, 1944" | January 28, 1944 | data-sort-value="Jenner William E." | William E. Jenner (R) | November 7, 1944 |
| Oregon (Class 2) | data-sort-value="McNary Charles L." | Charles L. McNary (R) | data-sort-value="February 25, 1944" | Died February 25, 1944 | data-sort-value="Cordon Guy" | Guy Cordon (R) | data-sort-value="March 4, 1944" | March 4, 1944 | data-sort-value="Cordon Guy" | Guy Cordon (R) | November 7, 1944 |
| New Jersey (Class 1) | data-sort-value="Warren Barbour William" | William Warren Barbour (R) | data-sort-value="November 22, 1943" | Died November 22, 1943 | data-sort-value="Walsh Arthur" | Arthur Walsh (D) | data-sort-value="November 26, 1943" | November 26, 1943 | data-sort-value="Smith H. Alexander" | H. Alexander Smith (R) | November 7, 1944 |
| Massachusetts (Class 2) | data-sort-value="Lodge Henry Cabot Jr." | Henry Cabot Lodge Jr. (R) | data-sort-value="February 3, 1944" | Resigned February 3, 1944 | data-sort-value="Weeks Sinclair" | Sinclair Weeks (R) | data-sort-value="February 8, 1944" | February 8, 1944 | data-sort-value="Saltonstall Leverett" | Leverett Saltonstall (R) | November 7, 1944 |
| North Dakota (Class 2) | data-sort-value="Moses John" | John Moses (D) | data-sort-value="March 3, 1945" | Died March 3, 1945 | data-sort-value="Young Milton R." | Milton Young (R) | data-sort-value="March 12, 1945" | March 12, 1945 | data-sort-value="Young Milton R." | Milton Young (R) | June 25, 1946 |
| Alabama (Class 2) | data-sort-value="Bankhead John H. II" | John H. Bankhead II (D) | data-sort-value="June 12, 1946" | Died June 12, 1946 | data-sort-value="Swift George R." | George R. Swift (D) | data-sort-value="June 15, 1946" | June 15, 1946 | data-sort-value="Sparkman John" | John Sparkman (D) | November 5, 1946 |
| California (Class 1) | data-sort-value="Johnson Hiram" | Hiram Johnson (R) | data-sort-value="August 6, 1945" | Died August 6, 1945 | data-sort-value="Knowland William F." | William F. Knowland (R) | data-sort-value="August 26, 1945" | August 26, 1945 | data-sort-value="Knowland William F." | William F. Knowland (R) | November 5, 1946 |
| Connecticut (Class 1) | data-sort-value="Maloney Francis T." | Francis T. Maloney (D) | data-sort-value="January 16, 1945" | Died January 16, 1945 | data-sort-value="Hart Thomas C." | Thomas C. Hart (R) | data-sort-value="February 15, 1945" | February 15, 1945 | data-sort-value="Baldwin Raymond E." | Raymond E. Baldwin (R) | November 5, 1946 |
| Idaho (Class 2) | data-sort-value="Thomas John" | John Thomas (R) | data-sort-value="November 10, 1945" | Died November 10, 1945 | data-sort-value="Gossett Charles C." | Charles C. Gossett (D) | data-sort-value="November 17, 1945" | November 17, 1945 | data-sort-value="Dworshak Henry" | Henry Dworshak (R) | November 5, 1946 |
| Kentucky (Class 2) | data-sort-value="Chandler Happy" | Happy Chandler (D) | data-sort-value="November 1, 1945" | Resigned November 1, 1945 | data-sort-value="Stanfill William A." | William A. Stanfill (R) | data-sort-value="November 19, 1945" | November 19, 1945 | data-sort-value="Sherman Cooper John" | John Sherman Cooper (R) | November 5, 1946 |
| Ohio (Class 1) | data-sort-value="Burton Harold H." | Harold H. Burton (R) | data-sort-value="September 30, 1945" | Resigned September 30, 1945 | data-sort-value="Huffman James W." | James W. Huffman (D) | data-sort-value="October 8, 1945" | October 8, 1945 | data-sort-value="Taft Kingsley A." | Kingsley A. Taft (R) | November 5, 1946 |
| Virginia (Class 2) | data-sort-value="Glass Carter" | Carter Glass (D) | data-sort-value="May 28, 1946" | Died May 28, 1946 | data-sort-value="Burch Thomas G." | Thomas G. Burch (D) | data-sort-value="May 31, 1946" | May 31, 1946 | data-sort-value="Robertson A. Willis" | A. Willis Robertson (D) | November 5, 1946 |
| Mississippi (Class 1) | data-sort-value="Bilbo Theodore G." | Theodore G. Bilbo (D) | data-sort-value="August 24, 1947" | Died August 24, 1947 | No appointment | data-sort-value="Stennis John C." | John C. Stennis (D) | November 5, 1947 | |||
| New York (Class 3) | data-sort-value="Wagner Robert F." | Robert F. Wagner (D) | data-sort-value="June 28, 1949" | Resigned June 28, 1949 | data-sort-value="Dulles John Foster" | John Foster Dulles (R) | data-sort-value="July 7, 1949" | July 7, 1949 | data-sort-value="Lehman Herbert" | Herbert H. Lehman (D) | November 8, 1949 |
| North Carolina (Class 2) | data-sort-value="Broughton J. Melville" | J. Melville Broughton (D) | data-sort-value="March 6, 1949" | Died March 6, 1949 | data-sort-value="Porter Graham Frank" | Frank Porter Graham (D) | data-sort-value="March 29, 1949" | March 29, 1949 | data-sort-value="Smith Willis" | Willis Smith (D) | November 7, 1950 |
| Kansas (Class 3) | data-sort-value="Reed Clyde M." | Clyde M. Reed (R) | data-sort-value="November 8, 1949" | Died November 8, 1949 | data-sort-value="Darby Harry" | Harry Darby (R) | data-sort-value="December 2, 1949" | December 2, 1949 | data-sort-value="Carlson Frank" | Frank Carlson (R) | November 7, 1950 |
| Idaho (Class 2) | data-sort-value="Miller Bert H." | Bert H. Miller (D) | data-sort-value="October 8, 1949" | Died October 8, 1949 | data-sort-value="Dworshak Henry" | Henry Dworshak (R) | data-sort-value="October 14, 1949" | October 14, 1949 | data-sort-value="Dworshak Henry" | Henry Dworshak (R) | November 7, 1950 |
| Connecticut (Class 3) | data-sort-value="McMahon Brien" | Brien McMahon (D) | data-sort-value="July 28, 1952" | Died July 28, 1952 | data-sort-value="Purtell William A." | William A. Purtell (R) | data-sort-value="August 29, 1952" | August 29, 1952 | data-sort-value="Bush Prescott" | Prescott Bush (R) | November 4, 1952 |
| Kentucky (Class 2) | data-sort-value="Chapman Virgil" | Virgil Chapman (D) | data-sort-value="March 8, 1951" | Died March 8, 1951 | data-sort-value="Underwood Thomas R." | Thomas R. Underwood (D) | data-sort-value="March 19, 1951" | March 19, 1951 | data-sort-value="Cooper John Sherman" | John Sherman Cooper (R) | November 4, 1952 |
| Michigan (Class 1) | data-sort-value="Vandenberg Arthur" | Arthur Vandenberg (R) | data-sort-value="April 18, 1951" | Died April 18, 1951 | data-sort-value="Moody Blair" | Blair Moody (D) | data-sort-value="April 23, 1951" | April 23, 1951 | data-sort-value="Potter Charles E." | Charles E. Potter (R) | November 4, 1952 |
| Nebraska (Class 2) | data-sort-value="Wherry Kenneth S." | Kenneth S. Wherry (R) | data-sort-value="November 29, 1951" | Died November 29, 1951 | data-sort-value="Seaton Fred A." | Fred A. Seaton (R) | data-sort-value="December 10, 1951" | December 10, 1951 | data-sort-value="Griswold Dwight" | Dwight Griswold (R) | November 4, 1952 |
| California (Class 3) | data-sort-value="Nixon Richard" | Richard Nixon (R) | data-sort-value="January 1, 1953" | Resigned January 1, 1953 Elected as vice president | data-sort-value="Kuchel Thomas" | Thomas Kuchel (R) | data-sort-value="January 2, 1953" | January 2, 1953 | data-sort-value="Kuchel Thomas" | Thomas Kuchel (R) | November 2, 1954 |
| North Carolina (Class 2) | data-sort-value="Smith Willis" | Willis Smith (D) | data-sort-value="June 26, 1953" | Died June 26, 1953 | data-sort-value="Lennon Alton A." | Alton Lennon (D) | data-sort-value="July 15, 1953" | July 15, 1953 | data-sort-value="Scott W. Kerr" | Kerr Scott (D) | November 2, 1954 |
| North Carolina (Class 3) | data-sort-value="Hoey Clyde R." | Clyde R. Hoey (D) | data-sort-value="May 12, 1954" | Died May 12, 1954 | data-sort-value="Ervin Sam" | Sam Ervin (D) | data-sort-value="June 5, 1954" | June 5, 1954 | data-sort-value="Ervin Sam" | Sam Ervin (D) | |
| Nebraska (Class 1) | data-sort-value="Butler Hugh A." | Hugh Butler (R) | data-sort-value="July 1, 1954" | Died July 1, 1954 | data-sort-value="Reynolds Samuel W." | Sam Reynolds (R) | data-sort-value="July 7, 1954" | July 7, 1954 | data-sort-value="Hruska Roman L." | Roman Hruska (R) | November 2, 1954 |
| Nebraska (Class 2) | data-sort-value="Griswold Dwight P." | Dwight Griswold (R) | data-sort-value="April 12, 1954" | Died April 12, 1954 | data-sort-value="Bowring Eva K." | Eva Bowring (R) | data-sort-value="April 26, 1954" | April 26, 1954 | data-sort-value="Abel Hazel H." | Hazel Abel (R) | |
| Kentucky (Class 2) | data-sort-value="Barkley Alben W." | Alben Barkley (D) | data-sort-value="April 30, 1956" | Died April 30, 1956 | data-sort-value="Humphreys Robert" | Robert Humphreys (D) | data-sort-value="June 25, 1956" | June 25, 1956 | data-sort-value="Cooper John Sherman" | John Sherman Cooper (R) | November 6, 1956 |
| West Virginia (Class 1) | data-sort-value="Kilgore Harley M." | Harley M. Kilgore (D) | data-sort-value="February 28, 1956" | Died February 28, 1956 | data-sort-value="Laird William III" | William Laird III (D) | data-sort-value="March 13, 1956" | March 13, 1956 | data-sort-value="Revercomb W. Chapman" | Chapman Revercomb (R) | November 6, 1956 |
| South Carolina (Class 2) | data-sort-value="Thurmond Strom" | Strom Thurmond (D) | data-sort-value="April 4, 1956" | Resigned April 4, 1956 | data-sort-value="Wofford Thomas A." | Thomas A. Wofford (D) | data-sort-value="April 5, 1956" | April 5, 1956 | data-sort-value="Thurmond Strom" | Strom Thurmond (D) | November 6, 1956 |
| Texas (Class 1) | data-sort-value="Daniel Price" | Price Daniel (D) | data-sort-value="January 14, 1957" | Resigned January 14, 1957 | data-sort-value="Blakley William A." | William Blakley (D) | data-sort-value="January 17, 1957" | January 17, 1957 | data-sort-value="Yarborough Ralph W." | Ralph Yarborough (D) | April 2, 1957 |
| Wisconsin (Class 1) | data-sort-value="McCarthy Joseph" | Joseph McCarthy (R) | data-sort-value="May 2, 1957" | Died May 2, 1957 | No appointment | data-sort-value="Proxmire William" | William Proxmire (D) | August 27, 1957 | |||
| West Virginia (Class 2) | data-sort-value="Neely Matthew M." | Matthew M. Neely (D) | data-sort-value="January 18, 1958" | Died January 18, 1958 | data-sort-value="Hoblitzell John D. Jr." | John D. Hoblitzell Jr. (R) | data-sort-value="January 25, 1958" | January 25, 1958 | data-sort-value="Randolph Jennings" | Jennings Randolph (D) | November 4, 1958 |
| North Carolina (Class 2) | data-sort-value="Scott W. Kerr" | W. Kerr Scott (D) | data-sort-value="April 16, 1958" | Died April 16, 1958 | data-sort-value="Jordan B. Everett" | B. Everett Jordan (D) | data-sort-value="April 19, 1958" | April 19, 1958 | data-sort-value="Jordan B. Everett" | B. Everett Jordan (D) | November 4, 1958 |
| North Dakota (Class 1) | data-sort-value="Langer William" | William Langer (R) | data-sort-value="November 8, 1959" | Died November 8, 1959 | data-sort-value="Brunsdale Clarence" | Clarence Brunsdale (R) | data-sort-value="November 19, 1959" | November 19, 1959 | data-sort-value="Burdick Quentin" | Quentin Burdick (D-NPL) | June 28, 1960 |
| Missouri (Class 1) | data-sort-value="Hennings Thomas C. Jr." | Thomas C. Hennings Jr. (D) | data-sort-value="September 13, 1960" | Died September 13, 1960 | data-sort-value="Long Edward V." | Edward V. Long (D) | data-sort-value="September 23, 1960" | September 23, 1960 | data-sort-value="Long Edward V." | Edward V. Long (D) | November 8, 1960 |
| Oregon (Class 2) | data-sort-value="Neuberger Richard L." | Richard Neuberger (D) | data-sort-value="March 9, 1960" | Died March 9, 1960 | data-sort-value="Lusk Hall S." | Hall Lusk (D) | data-sort-value="March 16, 1960" | March 16, 1960 | data-sort-value="Neuberger Maurine" | Maurine Neuberger (D) | November 8, 1960 |
| Texas (Class 2) | data-sort-value="Johnson Lyndon B." | Lyndon Johnson (D) | data-sort-value="January 3, 1961" | Resigned January 3, 1961 Elected as vice president | data-sort-value="Blakley William A." | William Blakley (D) | data-sort-value="January 3, 1961" | January 3, 1961 | data-sort-value="Tower John" | John Tower (R) | May 27, 1961 |
| Massachusetts (Class 1) | data-sort-value="Kennedy John F." | John F. Kennedy (D) | data-sort-value="December 22, 1960" | Resigned December 22, 1960 Elected as president | data-sort-value="Smith Benjamin II" | Benjamin A. Smith II (D) | data-sort-value="December 27, 1960" | December 27, 1960 | data-sort-value="Kennedy Ted" | Ted Kennedy (D) | November 6, 1962 |
| New Hampshire (Class 2) | data-sort-value="Bridges Styles" | Styles Bridges (R) | data-sort-value="November 26, 1961" | Died November 26, 1961 | data-sort-value="Murphy Maurice J. Jr." | Maurice J. Murphy Jr. (R) | data-sort-value="December 7, 1961" | December 7, 1961 | data-sort-value="McIntyre Thomas" | Thomas McIntyre (D) | November 6, 1962 |
| Kansas (Class 2) | data-sort-value="Schoeppel Andrew" | Andrew Schoeppel (R) | data-sort-value="January 21, 1962" | Died January 21, 1962 | data-sort-value="Pearson James B." | James Pearson (R) | data-sort-value="January 31, 1962" | January 31, 1962 | data-sort-value="Pearson James B." | James Pearson (R) | November 6, 1962 |
| Idaho (Class 2) | data-sort-value="Dworshak Henry" | Henry Dworshak (R) | data-sort-value="July 23, 1962" | Died July 23, 1962 | data-sort-value="Jordan Leonard B." | Len Jordan (R) | data-sort-value="August 6, 1962" | August 6, 1962 | data-sort-value="Jordan Leonard B." | Len Jordan (R) | November 6, 1962 |
| Wyoming (Class 2) | data-sort-value="Thomson Edwin Keith" | Edwin Keith Thomson (R) | data-sort-value="December 9, 1960" | Died December 9, 1960 | data-sort-value="Hickey John J." | John J. Hickey (D) | data-sort-value="January 3, 1961" | January 3, 1961 | data-sort-value="Simpson Milward L." | Milward Simpson (R) | November 6, 1962 |
| New Mexico (Class 1) | data-sort-value="Chavez Dennis" | Dennis Chavez (D) | data-sort-value="November 18, 1962" | Died November 18, 1962 | data-sort-value="Mechem Edwin L." | Edwin Mechem (R) | data-sort-value="November 30, 1962" | November 30, 1962 | data-sort-value="Montoya Joseph" | Joseph Montoya (D) | November 3, 1964 |
| Oklahoma (Class 2) | data-sort-value="Kerr Robert S." | Robert S. Kerr (D) | data-sort-value="January 1, 1963" | Died January 1, 1963 | data-sort-value="Edmondson J. Howard" | J. Howard Edmondson (D) | data-sort-value="January 6, 1963" | January 6, 1963 | data-sort-value="Harris Fred R." | Fred R. Harris (D) | November 3, 1964 |
| Tennessee (Class 2) | data-sort-value="Kefauver Estes" | Estes Kefauver (D) | data-sort-value="August 10, 1963" | Died August 10, 1963 | data-sort-value="Walters Herbert S." | Herbert Walters (D) | data-sort-value="August 20, 1963" | August 20, 1963 | data-sort-value="Bass Ross" | Ross Bass (D) | November 3, 1964 |
| South Carolina (Class 3) | data-sort-value="Johnston Olin D." | Olin Johnston (D) | data-sort-value="April 18, 1965" | Died April 18, 1965 | data-sort-value="Russell Donald S." | Donald Russell (D) | data-sort-value="April 22, 1965" | April 22, 1965 | data-sort-value="Hollings Ernest" | Fritz Hollings (D) | November 8, 1966 |
| Virginia (Class 1) | data-sort-value="Byrd Harry F. Sr." | Harry F. Byrd Sr. (D) | data-sort-value="November 10, 1965" | Resigned November 10, 1965 | data-sort-value="Byrd Harry F. Jr." | Harry F. Byrd Jr. (D) | data-sort-value="November 12, 1965" | November 12, 1965 | data-sort-value="Byrd Harry F. Jr." | Harry F. Byrd Jr. (D) | November 8, 1966 |
| Alaska (Class 2) | data-sort-value="Bartlett Bob" | Bob Bartlett (D) | data-sort-value="December 11, 1968" | Died December 11, 1968 | data-sort-value="Stevens Ted" | Ted Stevens (R) | data-sort-value="December 24, 1968" | December 24, 1968 | data-sort-value="Stevens Ted" | Ted Stevens (R) | November 3, 1970 |
| Illinois (Class 3) | data-sort-value="Dirksen Everett" | Everett Dirksen (R) | data-sort-value="September 7, 1969" | Died September 7, 1969 | data-sort-value="Smith Ralph Tyler" | Ralph Tyler Smith (R) | data-sort-value="September 17, 1969" | September 17, 1969 | data-sort-value="Stevenson Adlai III" | Adlai Stevenson III (D) | November 3, 1970 |
| Vermont (Class 1) | data-sort-value="Prouty Winston L." | Winston L. Prouty (R) | data-sort-value="September 10, 1971" | Died September 10, 1971 | data-sort-value="Stafford Robert" | Robert Stafford (R) | data-sort-value="September 16, 1971" | September 16, 1971 | data-sort-value="Stafford Robert" | Robert Stafford (R) | January 7, 1972 |
| Georgia (Class 2) | data-sort-value="Russell Jr. Richard" | Richard Russell Jr. (D) | data-sort-value="January 21, 1971" | Died January 21, 1971 | data-sort-value="Gambrell David H." | David H. Gambrell (D) | data-sort-value="February 1, 1971" | February 1, 1971 | data-sort-value="Nunn Sam" | Sam Nunn (D) | November 7, 1972 |
| New Hampshire (Class 3) | Failure to elect by January 3, 1975 | data-sort-value="Cotton Norris H." | Norris H. Cotton (R) | data-sort-value="August 8, 1975" | August 8, 1975 | data-sort-value="Durkin John A." | John A. Durkin (D) | September 16, 1975 | |||
| Minnesota (Class 1) | data-sort-value="Humphrey Hubert" | Hubert Humphrey (D) | data-sort-value="January 13, 1978" | Died January 13, 1978 | data-sort-value="Humphrey Muriel" | Muriel Humphrey (D) | data-sort-value="January 25, 1978" | January 25, 1978 | data-sort-value="Durenberger David" | David Durenberger (R) | November 7, 1978 |
| Alabama (Class 3) | data-sort-value="Allen James" | James Allen (D) | data-sort-value="June 1, 1978" | Died June 1, 1978 | data-sort-value="Allen Maryon" | Maryon Pittman Allen (D) | data-sort-value="June 8, 1978" | June 8, 1978 | data-sort-value="Stewart Donald W." | Donald Stewart (D) | November 7, 1978 |
| Washington (Class 1) | data-sort-value="Jackson Henry Scoop" | Henry M. Jackson (D) | data-sort-value="September 1, 1983" | Died September 1, 1983 | data-sort-value="Evans Daniel J." | Daniel J. Evans (R) | data-sort-value="September 8, 1983" | September 8, 1983 | data-sort-value="Evans Daniel J." | Daniel J. Evans (R) | November 8, 1983 |
| North Carolina (Class 3) | data-sort-value="East John" | John Porter East (R) | data-sort-value="June 29, 1986" | Died June 29, 1986 | data-sort-value="Broyhill Jim" | Jim Broyhill (R) | data-sort-value="July 14, 1986" | July 14, 1986 | data-sort-value="Sanford Terry" | Terry Sanford (D) | November 8, 1986 |
| Indiana (Class 3) | data-sort-value="Quayle Dan" | Dan Quayle (R) | data-sort-value="January 3, 1989" | Resigned January 3, 1989 Elected as vice president | data-sort-value="Coats Dan" | Dan Coats (R) | data-sort-value="January 3, 1989" | January 3, 1989 | data-sort-value="Coats Dan" | Dan Coats (R) | November 6, 1990 |
| Hawaii (Class 1) | data-sort-value="Matsunaga Spark" | Spark Matsunaga (D) | data-sort-value="April 15, 1990" | Died April 15, 1990 | data-sort-value="Akaka Daniel" | Daniel Akaka (D) | data-sort-value="May 16, 1990" | May 16, 1990 | data-sort-value="Akaka Daniel" | Daniel Akaka (D) | November 6, 1990 |
| Pennsylvania (Class 1) | data-sort-value="Heinz H. John III" | H. John Heinz III (R) | data-sort-value="April 4, 1991" | Died April 4, 1991 | data-sort-value="Wofford Harris" | Harris Wofford (D) | data-sort-value="May 9, 1991" | May 9, 1991 | data-sort-value="Wofford Harris" | Harris Wofford (D) | November 5, 1991 |
| California (Class 1) | data-sort-value="Wilson Pete" | Pete Wilson (R) | data-sort-value="January 7, 1991" | Resigned January 7, 1991 | data-sort-value="Seymour John" | John Seymour (R) | data-sort-value="January 10, 1991" | January 10, 1991 | data-sort-value="Feinstein Dianne" | Dianne Feinstein (D) | November 3, 1992 |
| North Dakota (Class 1) | data-sort-value="Burdick Quentin" | Quentin Burdick (D) | data-sort-value="September 8, 1992" | Died September 8, 1992 | data-sort-value="Burdick Jocelyn" | Jocelyn Burdick (D) | data-sort-value="September 16, 1992" | September 16, 1992 | data-sort-value="Conrad Kent" | Kent Conrad (D) | December 4, 1992 |
| Texas (Class 1) | data-sort-value="Bentsen Lloyd" | Lloyd Bentsen (D) | data-sort-value="January 20, 1993" | Resigned January 20, 1993 | data-sort-value="Krueger Bob" | Bob Krueger (D) | data-sort-value="January 21, 1993" | January 21, 1993 | data-sort-value="Hutchison Kay Bailey" | Kay Bailey Hutchison (R) | June 5, 1993 |
| Tennessee (Class 2) | data-sort-value="Gore Al" | Al Gore (D) | data-sort-value="January 3, 1993" | Resigned January 3, 1993 Elected as vice president | data-sort-value="Mathews Harlan" | Harlan Mathews (D) | data-sort-value="January 3, 1993" | January 3, 1993 | data-sort-value="Thompson Fred" | Fred Thompson (R) | November 8, 1994 |
| Oklahoma (Class 2) | data-sort-value="Boren David" | David Boren (D) | data-sort-value="November 15, 1994" | Resigned November 15, 1994 | No appointment | data-sort-value="Inhofe Jim" | Jim Inhofe (R) | November 8, 1994 | |||
| Oregon (Class 3) | data-sort-value="Packwood Bob" | Bob Packwood (R) | data-sort-value="October 1, 1995" | Resigned October 1, 1995 | No appointment | data-sort-value="Wyden Ron" | Ron Wyden (D) | January 30, 1996 | |||
| Kansas (Class 3) | data-sort-value="Dole Bob" | Bob Dole (R) | data-sort-value="June 11, 1996" | Resigned June 11, 1996 | data-sort-value="Frahm Sheila" | Sheila Frahm (R) | data-sort-value="June 11, 1996" | June 11, 1996 | data-sort-value="Brownback Sam" | Sam Brownback (R) | November 5, 1996 |
| Georgia (Class 3) | data-sort-value="Coverdell Paul" | Paul Coverdell (R) | data-sort-value="July 18, 2000" | Died July 18, 2000 | data-sort-value="Miller Zell" | Zell Miller (D) | data-sort-value="July 24, 2000" | July 24, 2000 | data-sort-value="Miller Zell" | Zell Miller (D) | November 7, 2000 |
| Missouri (Class 1) | data-sort-value="Carnahan Mel" | Mel Carnahan (D) | data-sort-value="October 16, 2000" | Died October 16, 2000 | data-sort-value="Carnahan Jean" | Jean Carnahan (D) | data-sort-value="January 3, 2001" | January 3, 2001 | data-sort-value="Talent Jim" | Jim Talent (R) | November 5, 2002 |
| Wyoming (Class 1) | data-sort-value="Thomas Craig L." | Craig L. Thomas (R) | data-sort-value="June 4, 2007" | Died June 4, 2007 | data-sort-value="Barrasso John" | John Barrasso (R) | data-sort-value="June 25, 2007" | June 25, 2007 | data-sort-value="Barrasso John" | John Barrasso (R) | November 4, 2008 |
| Mississippi (Class 1) | data-sort-value="Lott Trent" | Trent Lott (R) | data-sort-value="December 18, 2007" | Resigned December 18, 2007 | data-sort-value="Wicker Roger" | Roger Wicker (R) | data-sort-value="December 31, 2007" | December 31, 2007 | data-sort-value="Wicker Roger" | Roger Wicker (R) | November 4, 2008 |
| Massachusetts (Class 1) | data-sort-value="Kennedy Ted" | Ted Kennedy (D) | data-sort-value="August 25, 2009" | Died August 25, 2009 | data-sort-value="Kirk Paul G." | Paul G. Kirk (D) | data-sort-value="September 24, 2009" | September 24, 2009 | data-sort-value="Brown Scott" | Scott Brown (R) | January 19, 2010 |
| Illinois (Class 3) | data-sort-value="Obama Barack" | Barack Obama (D) | data-sort-value="November 16, 2008" | Resigned November 16, 2008 Elected as president | data-sort-value="Burris Roland" | Roland Burris (D) | data-sort-value="January 12, 2009" | January 12, 2009 | data-sort-value="Kirk Mark" | Mark Kirk (R) | November 2, 2010 |
| Delaware (Class 2) | data-sort-value="Biden Joe" | Joe Biden (D) | data-sort-value="January 15, 2009" | Resigned January 15, 2009 Elected as vice president | data-sort-value="Kaufman Ted" | Ted Kaufman (D) | data-sort-value="January 16, 2009" | January 16, 2009 | data-sort-value="Coons Chris" | Chris Coons (D) | November 2, 2010 |
| New York (Class 1) | data-sort-value="Clinton Hillary" | Hillary Clinton (D) | data-sort-value="January 21, 2009" | Resigned January 21, 2009 | data-sort-value="Gillibrand Kirsten" | Kirsten Gillibrand (D) | data-sort-value="January 27, 2009" | January 27, 2009 | data-sort-value="Gillibrand Kirsten" | Kirsten Gillibrand (D) | November 2, 2010 |
| West Virginia (Class 1) | data-sort-value="Byrd Robert" | Robert Byrd (D) | data-sort-value="June 28, 2010" | Died June 28, 2010 | data-sort-value="Goodwin Carte" | Carte Goodwin (D) | data-sort-value="July 20, 2010" | July 20, 2010 | data-sort-value="Manchin Joe" | Joe Manchin (D) | November 2, 2010 |
| Massachusetts (Class 2) | data-sort-value="Kerry John" | John Kerry (D) | data-sort-value="February 1, 2013" | Resigned February 1, 2013 | data-sort-value="Cowan Mo" | Mo Cowan (D) | data-sort-value="February 1, 2013" | February 1, 2013 | data-sort-value="Markey Ed" | Ed Markey (D) | June 25, 2013 |
| New Jersey (Class 2) | data-sort-value="Lautenberg Frank" | Frank Lautenberg (D) | data-sort-value="June 3, 2013" | Died June 3, 2013 | data-sort-value="Chiesa Jeffrey" | Jeffrey Chiesa (R) | data-sort-value="June 10, 2013" | June 10, 2013 | data-sort-value="Booker Cory" | Cory Booker (D) | October 16, 2013 |
| South Carolina (Class 3) | data-sort-value="DeMint Jim" | Jim DeMint (R) | data-sort-value="January 1, 2013" | Resigned January 1, 2013 | data-sort-value="Scott Tim" | Tim Scott (R) | data-sort-value="January 2, 2013" | January 2, 2013 | data-sort-value="Scott Tim" | Tim Scott (R) | November 4, 2014 |
| Hawaii (Class 3) | data-sort-value="Inouye Daniel" | Daniel Inouye (D) | data-sort-value="December 17, 2012" | Died December 17, 2012 | data-sort-value="Schatz Brian" | Brian Schatz (D) | data-sort-value="December 26, 2012" | December 26, 2012 | data-sort-value="Schatz Brian" | Brian Schatz (D) | November 4, 2014 |
| Oklahoma (Class 3) | data-sort-value="Coburn Tom" | Tom Coburn (R) | data-sort-value="January 3, 2015" | Resigned January 3, 2015 | No appointment | data-sort-value="Lankford James" | James Lankford (R) | November 4, 2014 | |||
| Alabama (Class 2) | data-sort-value="Sessions Jeff" | Jeff Sessions (R) | data-sort-value="February 8, 2017" | Resigned February 8, 2017 | data-sort-value="Strange Luther" | Luther Strange (R) | data-sort-value="February 9, 2017" | February 9, 2017 | data-sort-value="Jones Doug" | Doug Jones (D) | December 12, 2017 |
| Minnesota (Class 2) | data-sort-value="Franken Al" | Al Franken (D) | data-sort-value="January 2, 2018" | Resigned January 2, 2018 | data-sort-value="Smith Tina" | Tina Smith (D) | data-sort-value="January 3, 2018" | January 3, 2018 | data-sort-value="Smith Tina" | Tina Smith (D) | November 6, 2018 |
| Mississippi (Class 2) | data-sort-value="Cochran Thad" | Thad Cochran (R) | data-sort-value="April 1, 2018" | Resigned April 1, 2018 | data-sort-value="Hyde-Smith Cindy" | Cindy Hyde-Smith (R) | data-sort-value="April 2, 2018" | April 2, 2018 | data-sort-value="Hyde-Smith Cindy" | Cindy Hyde-Smith (R) | November 6, 2018 |
| Arizona (Class 3) | John McCain (R) | Died August 25, 2018 | data-sort-value="Kyl Jon" | Jon Kyl (R) | data-sort-value="September 4, 2018" | September 4, 2018 – December 31, 2018 (resigned) | Mark Kelly (D) | November 3, 2020 | |||
| data-sort-value="McSally Martha" | Martha McSally (R) | data-sort-value="January 3, 2019" | January 3, 2019 | ||||||||
| Georgia (Class 3) | data-sort-value="Isakson Johnny" | Johnny Isakson (R) | data-sort-value="December 31, 2019" | Resigned December 31, 2019 | data-sort-value="Loeffler Kelly" | Kelly Loeffler (R) | data-sort-value="January 6, 2020" | January 6, 2020 | data-sort-value="Warnock Raphael" | Raphael Warnock (D) | January 5, 2021 |
| California (Class 3) | data-sort-value="Harris Kamala" | Kamala Harris (D) | Resigned January 18, 2021 Elected as vice president | data-sort-value="Padilla Alex" | Alex Padilla (D) | data-sort-value="January 20, 2021" | January 20, 2021 | data-sort-value="Padilla Alex" | Alex Padilla (D) | November 8, 2022 | |
| Oklahoma (Class 2) | data-sort-value="Inhofe Jim" | Jim Inhofe (R) | data-sort-value="January 3, 2023" | Resigned January 3, 2023 | No appointment | data-sort-value="Mullin Markwayne" | Markwayne Mullin (R) | November 8, 2022 | |||
| Nebraska (Class 2) | data-sort-value="Sasse Ben" | Ben Sasse (R) | data-sort-value="January 8, 2023" | Resigned January 8, 2023 | data-sort-value="Ricketts Pete" | Pete Ricketts (R) | data-sort-value="January 12, 2023" | January 12, 2023 | TBD | November 5, 2024 | |
| California (Class 1) | data-sort-value="Feinstein Dianne" | Dianne Feinstein (D) | Died September 29, 2023 | data-sort-value="Butler Laphonza" | Laphonza Butler (D) | data-sort-value="October 1, 2023" | October 3, 2023 | TBD | November 5, 2024 | ||
| State | Senator | Vacancy event | Senator | Date | Senator | Date | |||||
| Original | Appointee | Election winner | |||||||||