Columns: State (class) | Vacator | Reason for change | Successor | Date of successors formal installation
Missouri (3) | Vacant | Did not take seat until after Congress commenced | Waldo P. Johnson (D) | March 17, 1861 | Kansas (2) | Vacant | Election not recognized by US Senate | James H. Lane (R) | April 4, 1861 | Kansas (3) | Vacant | Election not recognized by US Senate | Samuel C. Pomeroy (R) | April 4, 1861 | North Carolina (2) | Thomas Bragg (D) | Withdrew March 6, 1861; expelled later in 1861. | Vacant thereafter | Vacant thereafter | Texas (1) | Louis T. Wigfall (D) | Withdrew March 23, 1861 | Vacant | Vacant for remainder of term | North Carolina (3) | Thomas L. Clingman (D) | Withdrew March 28, 1861; expelled later in 1861. | Vacant thereafter | Vacant thereafter | Illinois (2) | Stephen A. Douglas (D) | Died June 3, 1861. Successor was appointed. | Orville H. Browning (R) | June 26, 1861 | Texas (2) | John Hemphill (D) | Expelled July ????, 1861 | Vacant | Vacant for remainder of term | Arkansas (2) | William K. Sebastian (D) | Expelled July 11, 1861 | Expelled July 11, 1861 | Vacant thereafter | Arkansas (3) | Charles B. Mitchel (D) | Expelled July 11, 1861 | Expelled July 11, 1861 | Vacant thereafter | Michigan (2) | Kinsley S. Bingham (R) | Died October 5, 1861. Successor was elected. | Jacob M. Howard (R) | January 17, 1862 | Tennessee (1) | Andrew Johnson (D) | Resigned March 4, 1862 | Vacant thereafter | Vacant thereafter | Rhode Island (1) | James F. Simmons (R) | Resigned August 15, 1862. Successor was elected. | Samuel G. Arnold (R) | December 1, 1862 | New Jersey (1) | John R. Thomson (D) | Died September 12, 1862. Successor was appointed. | Richard S. Field (R) | November 21, 1862