Columns: District | Vacator | Reason for change | Successor | Date successor seated
Illinois 6th | Vacant | Vacancy in term | John A. McClernand ( D ) | Seated November 8, 1859 | Ohio 14th | Cyrus Spink ( R ) | Died May 31, 1859 | Harrison G. O. Blake ( R ) | Seated October 11, 1859 | Virginia 4th | William Goode ( D ) | Died July 3, 1859 | Roger A. Pryor ( D ) | Seated December 7, 1859 | Michigan 1st | George B. Cooper ( D ) | Lost contested election May 15, 1860 | Francis P. Blair, Jr. ( R ) | Seated May 15, 1860 | Nebraska Territory At-large | Experience Estabrook | Lost contested election May 18, 1860 | Samuel G. Daily ( R ) | Seated May 18, 1860 | New York 31st | Silas M. Burroughs ( R ) | Died June 3, 1860 | Edwin R. Reynolds ( R ) | Seated December 5, 1860 | Missouri 1st | John R. Barret ( D ) | Lost contested election June 8, 1860 | William A. Howard ( R ) | Seated June 8, 1860 | Pennsylvania 8th | John Schwartz (ALD) | Died June 20, 1860 | Jacob K. McKenty ( D ) | Seated December 3, 1860 | Missouri 1st | William A. Howard ( R ) | Resigned June 25, 1860 | John R. Barret ( R ) | Seated December 3, 1860 | Mississippi 1st | Lucius Q. C. Lamar II ( D ) | Retired December ???, 1860 | Vacant | Not filled this term | South Carolina 3rd | Laurence M. Keitt ( D ) | Retired December ???, 1860 | Vacant | Not filled this term | South Carolina 1st | John McQueen ( D ) | Retired December 21, 1860 | Vacant | Not filled this term | South Carolina 2nd | William P. Miles ( D ) | Retired December 21, 1860 | Vacant | Not filled this term | South Carolina 4th | Milledge L. Bonham ( D ) | Retired December 21, 1860 | Vacant | Not filled this term | South Carolina 5th | John D. Ashmore ( D ) | Retired December 21, 1860 | Vacant | Not filled this term | South Carolina 6th | William W. Boyce ( D ) | Retired December 21, 1860 | Vacant | Not filled this term | Mississippi 2nd | Reuben Davis ( D ) | Withdrew January 12, 1861 | Vacant | Not filled this term | Mississippi 3rd | William Barksdale ( D ) | Withdrew January 12, 1861 | Vacant | Not filled this term | Mississippi 4th | Otho R. Singleton ( D ) | Withdrew January 12, 1861 | Vacant | Not filled this term | Mississippi 5th | John J. McRae ( D ) | Withdrew January 12, 1861 | Vacant | Not filled this term | Alabama 1st | James A. Stallworth ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 1st | James A. Stallworth ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 2nd | James L. Pugh ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 3rd | David Clopton ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 4th | Sydenham Moore ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 5th | George S. Houston ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Alabama 7th | Jabez L. M. Curry ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Florida At-large | George S. Hawkins ( D ) | Withdrew January 21, 1861 | Vacant | Not filled this term | Georgia 1st | Peter E. Love ( D ) | Retired January 23, 1861 | Vacant | Not filled this term | Georgia 2nd | Martin J. Crawford ( D ) | Withdrew January 23, 1861 | Vacant | Not filled this term | Georgia 3rd | Thomas Hardeman, Jr. ( O ) | Withdrew January 23, 1861 | Vacant | Not filled this term | Georgia 4th | Lucius J. Gartrell ( D ) | Retired January 23, 1861 | Vacant | Not filled this term | Georgia 5th | John W. H. Underwood ( D ) | Withdrew January 23, 1861 | Vacant | Not filled this term | Georgia 6th | James Jackson ( D ) | Retired January 23, 1861 | Vacant | Not filled this term | Georgia 7th | Joshua Hill ( KN ) | Resigned January 23, 1861 | Vacant | Not filled this term | Georgia 8th | John J. Jones ( D ) | Withdrew January 23, 1861 | Vacant | Not filled this term | Kansas Territory At-large | Marcus J. Parrott ( R ) | Kansas was admitted to the Union January 29, 1861 | Seat eliminated | Seat eliminated | Kansas At-large | New Seat | Kansas was admitted to the Union January 29, 1861 | Martin F. Conway ( R ) | Seated November 8, 1859 | Alabama 6th | Williamson R. W. Cobb ( D ) | Withdrew January 30, 1861 | Vacant | Not filled this term