F. Long (R) |- | | style="font-size:80%" | Vacancy caused by House declaring Charles H. Prince not entitled to seat | nowrap | Stephen A. Corker (D) |- | | style="font-size:80%" | Failure to elect | nowrap | William P. Price (D) |- | | style="font-size:80%" | Vacancy caused by House declaring Pierce M. B. Young not entitled to seat. He was subsequently elected to fill the vacancy thus caused | nowrap | Pierce M. B. Young (D) |- | | nowrap | Elihu B. Washburne (R) | style="font-size:80%" | Resigned March 6, 1869, after being appointed United States Secretary of State | nowrap | Horatio C. Burchard (R) | December 6, 1869 |- | | nowrap | George S. Boutwell (R) | style="font-size:80%" | Resigned March 12, 1869, after being appointed United States Secretary of the Treasury | nowrap | George M. Brooks (R) | November 2, 1869 |- | | nowrap | John Moffet (D) | style="font-size:80%" | Lost contested election April 9, 1869 | nowrap | Leonard Myers (R) | April 9, 1869 |- | | nowrap | Benjamin F. Hopkins (R) | style="font-size:80%" | Died January 1, 1870 | nowrap | David Atwood (R) | February 23, 1870 |- | | nowrap | Truman H. Hoag (D) | style="font-size:80%" | Died February 5, 1870 | nowrap | Erasmus D. Peck (R) | April 23, 1870 |- | | nowrap | George W. Greene (D) | style="font-size:80%" | Lost contested election February 17, 1870 | nowrap | Charles Van Wyck (R) | February 17, 1870 |- | | nowrap | Benjamin F. Whittemore (R) | style="font-size:80%" | Resigned February 24, 1870, pending an investigation of certain appointments to the US Military and Naval Academies | nowrap | Joseph Rainey (R) | December 12, 1870 |- | | nowrap | Jacob Golladay (D) | style="font-size:80%" | Resigned February 28, 1870 | nowrap | Joseph H. Lewis (D) | May 10, 1870 |- | | nowrap | John T. Deweese (R) | style="font-size:80%" | Resigned February 28, 1870, pending an investigation of certain appointments to the US Military and Naval Academies | nowrap | John Manning Jr. (D) | December 7, 1870 |- | | nowrap | John R. Reading (D) | style="font-size:80%" | Lost contested election April 13, 1870 | nowrap | Caleb N. Taylor (R) | April 13, 1870 |- | | nowrap | David Heaton (R)