had not been a candidate in the October 10, 1820, election for the next term, see below.Successor seated January 8, 1821. | nowrap | |- ! | Jesse Slocumb | | Democratic-Republican | 1817 | | Incumbent died December 20, 1820.New member elected February 7, 1821.Democratic-Republican hold.Successor seated February 7, 1821.Successor later re-elected in the August 9, 1821, election to the next term, see below. | nowrap | |} 17th Congress |- ! | George Robertson | | Democratic-Republican | 1816 | | Incumbent resigned sometime before the start of the new Congress.New member elected August 6, 1821.Democratic-Republican hold.Successor seated December 3, 1821. | nowrap | |- ! | John Linn | | Democratic-Republican | 1816 | | Incumbent died January 5, 1821.New member elected October 8, 1821.Democratic-Republican hold.Successor seated December 3, 1821. | nowrap | |- ! | John C. Wright | | Democratic-Republican | 1818 | | Incumbent member-elect declined to serve in the next term and resigned March 3, 1821.New member elected October 9, 1821.Democratic-Republican hold.Successor seated December 3, 1821. | nowrap | |- ! | James Duncan | | Democratic-Republican | 1820 | | Incumbent resigned in April 1821.New member elected October 9, 1821.Democratic-Republican hold.Successor seated December 12, 1821. | nowrap | |- ! | William Cox Ellis | | Federalist | 1820 | | Incumbent resigned July 20, 1821.New member elected October 9, 1821.Democratic-Republican hold.Successor seated December 12, 1821. | nowrap | |- ! | Selah Tuthill | | Democratic-Republican | 1821 | | Incumbent died September 7, 1821.New member elected November 6–8, 1821.Democratic-Republican hold.Successor seated December 3, 1821. | nowrap | |- ! | John S. Richards | | Democratic-Republican | 1820 | | Member-elect declined to serve.New member elected sometime in 1821.Democratic-Republican hold.Successor seated December 3, 1821. | nowrap | |- ! | Wingfield Bullock | | Democratic-Republican | 1820 | | Incumbent died October 13, 1821.New member elected November 22, 1821.Democratic-Republican hold.Successor seated January 2, 1822. | nowrap | |} Alabama Alabama elected its member August 5–6, 1821, after the term began but before the new Congress convened. |- ! | John Crowell | | Democratic-Republican | 1819 | | Incumbent retired.New member elected.Democratic-Republican hold. | nowrap | |} Arkansas Territory See Non-voting delegates, below. Connecticut Connecticut elected its members April 2, 1821, after the term began but before the new Congress convened. |- ! rowspan=7 | | James Stevens | |