This was the first election in Massachusetts after the separation of the former District of Maine as the new State of Maine, taking the old – districts with it.
Massachusetts elected its members November 6, 1820. Massachusetts had a majority requirement for election, which was not met in the necessitating two additional elections on January 8, 1821, and April 16, 1821, after the term began but before the new Congress convened.
| District | Incumbent | This race | ||||||
|---|---|---|---|---|---|---|---|---|
| Member | Party | First elected | Results | Candidates | ||||
| Jonathan Mason | Federalist | 1817 (Special) | Incumbent resigned May 15, 1820 to pursue his law practice. New member elected. Democratic-Republican gain. Successor also elected the same day to finish the term. | nowrap | √ Benjamin Gorham (Democratic-Republican) 57.9% Samuel Wells 40.2% Jesse Putname 1.4% Others 0.5% | |||
| Nathaniel Silsbee | Democratic-Republican | 1816 | Incumbent retired. New member elected late on the third ballot after the term began but before the Congress convened. Democratic-Republican hold. | nowrap | Willard Peele (I) 38.5% Gideon Barstow (Democratic-Republican) 34.0% Leverett Saltonstall I (Federalist) 27.4% Gideon Barstow (Democratic-Republican) 48.4% John Hooper (Federalist) 28.1% Willard Peele (I) 10.1% Charles Saunders 9.1% Others 4.4% √ Gideon Barstow (Democratic-Republican) 53.9% Timothy Pickering (Federalist) 44.7% Others 1.4% | |||
| Jeremiah Nelson | Federalist | 1804 1806 (Retired) 1814 | Incumbent re-elected. | nowrap | √ Jeremiah Nelson (Federalist) 85.7% Amos Spaulding 12.6% Others 1.7% | |||
| Timothy Fuller | Democratic-Republican | 1816 | Incumbent re-elected. | nowrap | √ Timothy Fuller (Democratic-Republican) 58.2% John Hart (Democratic-Republican) 20.9% Samuel P. Fay (Federalist) 17.8% Others 3.1% | |||
| Samuel Lathrop | Federalist | 1819 | Incumbent re-elected. | nowrap | √ Samuel Lathrop (Federalist) 73.7% Thomas Shepherd (Democratic-Republican) 26.3% | |||
| Samuel C. Allen | Federalist | 1816 | Incumbent re-elected. | nowrap | √ Samuel C. Allen (Federalist) 92.4% Others 7.6% | |||
| Henry Shaw | Democratic-Republican | 1816 | Incumbent retired. New member elected. Federalist gain. | nowrap | √ Henry W. Dwight (Federalist) 51.4% William P. Walker (Democratic-Republican) 43.9% Others 4.7% | |||
| Zabdiel Sampson | Democratic-Republican | 1816 | Incumbent resigned July 26, 1820. New member elected. Democratic-Republican hold. Successor later elected to finish the term. | nowrap | √ Aaron Hobart (Democratic-Republican) 54.4% William Baylies (Federalist) 45.6% | |||
| Walter Folger Jr. | Democratic-Republican | 1816 | Incumbent lost re-election. New member elected. Federalist gain. | nowrap | √ John Reed Jr. (Federalist) 65.9% Walter Folger Jr. (Democratic-Republican) 22.9% Others 11.2% | |||
| Marcus Morton | Democratic-Republican | 1816 | Incumbent lost re-election. New member elected. Federalist gain | nowrap | √ Francis Baylies (Federalist) 52.5% Marcus Morton (Democratic-Republican) 47.5% | |||
| Benjamin Adams | Federalist | 1816 | Incumbent lost re-election. New member elected. Democratic-Republican gain. | nowrap | √ Jonathan Russell (Democratic-Republican) 52.9% Benjamin Adams (Federalist) 42.9% Others 4.2% | |||
| Jonas Kendall | Federalist | 1818 | Incumbent lost re-election. New member elected. Federalist hold. | nowrap | √ Lewis Bigelow (Federalist) 51.7% Edmund Cushing (Democratic-Republican) 26.1% Jonas Kendall (Federalist) 22.1% | |||
| William Eustis | Democratic-Republican | 1800 1804 (Lost) 1820 (Special) | Incumbent re-elected. | nowrap | √ William Eustis (Democratic-Republican) 65.0% James Richardson (Federalist) 30.7% Richard Sullivan (Federalist) 4.3% | |||