| Alonzo J. Edgerton | |
| Office: | Judge of the United States District Court for the District of South Dakota |
| Term Start: | November 19, 1889 |
| Term End: | August 9, 1896 |
| Appointer: | Benjamin Harrison |
| Predecessor: | Seat established by 25 Stat. 676 |
| Successor: | John Emmett Carland |
| Jr/Sr1: | United States Senator |
| State1: | Minnesota |
| Term Start1: | March 12, 1881 |
| Term End1: | November 14, 1881 |
| Appointer1: | John S. Pillsbury |
| Predecessor1: | William Windom |
| Successor1: | William Windom |
| Office2: | Member of the Minnesota Senate |
| Term2: | 1858-1859 |
| Office3: | Member of the Minnesota House of Representatives |
| Birth Name: | Alonzo Jay Edgerton |
| Birth Date: | 7 June 1827 |
| Birth Place: | Rome, New York |
| Death Place: | Sioux Falls, South Dakota |
| Resting Place: | Evergreen Cemetery Mantorville, Minnesota |
| Party: | Republican |
| Education: | Wesleyan University read law |
| Allegiance: |  United StatesUnion |
| Branch: | Union Army |
| Serviceyears: | 1862–1867 |
| Rank: | Colonel |
| Unit: | 10th Minnesota Infantry Regiment 67th United States Colored Infantry Regiment |
| Battles: | American Civil War |
Alonzo Jay Edgerton (June 7, 1827 – August 9, 1896) was a United States senator from Minnesota and a United States district judge of the United States District Court for the District of South Dakota.
Born June 7, 1827, in Rome, Oneida County, New York, Edgerton graduated from Wesleyan University in 1850 and read law in 1855. At Wesleyan, he became a member of the Mystical Seven. He was admitted to the bar and entered private practice in Mantorville, Minnesota, from 1855 to 1861. He was prosecutor for Dodge County, Minnesota. He was a member of the Minnesota Senate from 1858 to 1859.[1] In 1862, during the American Civil War, Edgerton organized a company of militia which later constituted Company B of the Tenth Minnesota Infantry Volunteers.[2] By January 1864, he had risen to the rank of Colonel of the 67th Regiment Infantry United States Colored Troops.[2] He was brevetted a brigadier general on March 13, 1865, and confirmed on April 10, 1866.[2] He resumed private practice in Mantorville from 1867 to 1871. He was Railroad Commissioner for Minnesota from 1871 to 1874. Edgerton became a regent of the University of Minnesota in 1872.[2] He again resumed private practice in Mantorville from 1874 to 1877. He served as a member of the Minnesota House of Representatives and returned to private practice in Mantorville from 1878 to 1881.
Edgerton was appointed as a Republican to the United States Senate to fill the vacancy caused by the resignation of United States Senator William Windom and served from March 12, 1881, to October 30, 1881, during the 47th United States Congress, when a successor was elected.
Following his departure from Congress, Edgerton served as a Judge of the District Court for the District of Dakota Territory from 1881 to 1885. He returned to private practice in Mitchell, Dakota Territory (State of South Dakota from November 2, 1889) from 1885 to 1889. He served as President of the constitutional convention of South Dakota.[3]
Edgerton received a recess appointment from President Benjamin Harrison on November 19, 1889, to the United States District Court for the District of South Dakota, to a new seat authorized by 25 Stat. 676. He was nominated to the same position by President Harrison on December 16, 1889. He was confirmed by the United States Senate on January 16, 1890, and received his commission the same day. His service terminated on August 9, 1896, due to his death in Sioux Falls, South Dakota. He was interred in Evergreen Cemetery in Mantorville.
The town of Edgerton, Minnesota, is named in Edgerton's honor.[2] [4]