Resignation from the United States Senate
A member of the United States Senate can resign by writing a letter of resignation to the governor of the state that the senator represents. Under Article I, Section 3 of the Constitution of the United States, and under the Seventeenth Amendment, in case of a vacancy in the Senate resulting from resignation, the executive authority of the state can fill the vacancy by appointment unless the state legislature has provided for some other means of filling the vacancy, such as a special election. Whenever a senator needs to be appointed or elected, the Secretary of the Senate mails one of three forms to the state's governor to inform them of the proper wording to certify the appointment of a new Senator.
The first resignation from the Senate was that of William Paterson of New Jersey on November 13, 1790, who resigned in order to accept the office of Governor of New Jersey. His resignation was only the third time a person ceased to hold a seat in the Senate, which had first convened during the preceding year, 1789. The earlier ones resulted from the death of Senator William Grayson of Virginia, and the expiration of the term of the temporary senator John Walker of Virginia, who was appointed by the Governor of Virginia to hold that office until a successor could be elected in November.
Before 1796, eight senators resigned. Nine senators resigned during that year—a record-high number that stands to this day. Most resignations have been motivated either by declining health or a decision to accept another office. Sixteen persons have resigned from the Senate twice and two have resigned three times.
1789 to 1799
1800 to 1849
| Name | State | Date of resignation | Notes |
| Samuel Dexter | Massachusetts | May 30, 1800 | Resigned to take office as United States Secretary of War |
| John Laurance | New York | August 1, 1800 | |
| Benjamin Goodhue | Massachusetts | November 8, 1800 | |
| James Lloyd | Maryland | December 1, 1800 | |
| James Schureman | New Jersey | February 16, 1801 | |
| Henry Latimer | Delaware | February 28, 1801 | |
| Ray Greene | Rhode Island | March 5, 1801 | |
| Charles Pinckney | South Carolina | June 6, 1801 | |
| Samuel Livermore | New Hampshire | June 12, 1801 | |
| Elijah Paine | Vermont | September 1, 1801 | |
| John Armstrong, Jr. | New York | February 5, 1802 | |
| James Sheafe | New Hampshire | June 14, 1802 | |
| Dwight Foster | Massachusetts | March 2, 1803 | |
| DeWitt Clinton | New York | November 4, 1803 | |
| Theodorus Bailey | New York | January 16, 1804 | |
| John Armstrong, Jr. | New York | February 23, 1804 | |
| Abraham B. Venable | Virginia | June 7, 1804 | |
| John Armstrong, Jr. | New York | June 30, 1804 | |
| William H. Wells | Delaware | November 6, 1804 | |
| William Giles | Virginia | December 3, 1804 | |
| Andrew Moore | Virginia | December 3, 1804 | Resigned his Class 2 senatorship when elected to fill a vacant Class 1 senatorship |
| John Breckinridge | Kentucky | August 7, 1805 | |
| Robert Wright | Maryland | November 12, 1806 | |
| John Adair | Kentucky | November 18, 1806 | |
| David Stone | North Carolina | February 17, 1807 | |
| James Fenner | Rhode Island | September ??, 1807 | |
| Israel Smith | Vermont | October 1, 1807 | |
| John Smith | Ohio | April 25, 1808 | Resigned after being indicted but not expelled in a 19–10 vote |
| John Quincy Adams | Massachusetts | June 8, 1808 | |
| Samuel Maclay | Pennsylvania | January 4, 1809 | |
| Aaron Kitchell | New Jersey | March 3, 1809 | |
| Daniel Smith | Tennessee | March 31, 1809 | |
| John Milledge | Georgia | November 14, 1809 | |
| Buckner Thruston | Kentucky | December 18, 1809 | |
| Nahum Parker | New Hampshire | June 1, 1810 | |
| James Hillhouse | Connecticut | June 10, 1810 | |
| Return Meigs, Jr. | Ohio | December 8, 1810 | |
| Thomas Sumter | South Carolina | December 16, 1810 | |
| Jenkin Whiteside | Tennessee | October 8, 1811 | |
| Christopher Champlin | Rhode Island | October 12, 1811 | |
| Jean Noel Destréhan | Louisiana | October 1, 1812 | |
| James Bayard | Delaware | March 3, 1813 | |
| Dudley Chase | Vermont | March 3, 1813 | |
| William Crawford | Georgia | March 23, 1813 | |
| James Lloyd | Massachusetts | May 1, 1813 | |
| Chauncey Goodrich | Connecticut | May 13, 1813 | |
| George W. Campbell | Tennessee | February 11, 1814 | |
| Michael Leib | Pennsylvania | February 14, 1814 | |
| George Bibb | Kentucky | August 23, 1814 | |
| Thomas Worthington | Ohio | December 1, 1814 | |
| Jesse Bledsoe | Kentucky | December 24, 1814 | |
| David Stone | North Carolina | December 24, 1814 | |
| William Giles | Virginia | March 3, 1815 | |
| Francis Locke Jr. | North Carolina | December 5, 1815 | |
| William T. Barry | Kentucky | May 1, 1816 | |
| Christopher Gore | Massachusetts | May 30, 1816 | |
| John Taylor | South Carolina | November ??, 1816 | |
| Wyatt Bibb | Georgia | November 9, 1816 | |
| James Turner | North Carolina | November 21, 1816 | |
| Goodloe Harper | Maryland | December 6, 1816 | |
| Jeremiah Mason | New Hampshire | June 16, 1817 | |
| James Fisk | Vermont | January 8, 1818 | |
| George W. Campbell | Tennessee | April 20, 1818 | |
| Eli Ashmun | Massachusetts | May 10, 1818 | |
| George Troup | Georgia | September 23, 1818 | |
| John Forsyth | Georgia | February 17, 1819 | |
| John J. Crittenden | Kentucky | March 3, 1819 | |
| John Wayles Eppes | Virginia | December 4, 1819 | |
| Prentiss Mellen | Massachusetts | May 15, 1820 | |
| Walter Leake | Mississippi | May 15, 1820 | |
| William Logan | Kentucky | May 28, 1820 | |
| James Wilson | New Jersey | January 8, 1821 | |
| Freeman Walker | Georgia | August 6, 1821 | |
| Harrison Gray Otis | Massachusetts | May 30, 1822 | |
| John Williams Walker | Alabama | December 12, 1822 | |
| James Pleasants | Virginia | December 15, 1822 | |
| Caesar Augustus Rodney | Delaware | January 29, 1823 | |
| Samuel Southard | New Jersey | March 3, 1823 | |
| James Brown | Louisiana | December 10, 1823 | |
| Ninian Edwards | Illinois | March 3, 1824 | |
| Henry Johnson | Louisiana | May 27, 1824 | |
| James Barbour | Virginia | March 7, 1825 | |
| David Holmes | Mississippi | September 25, 1825 | |
| Andrew Jackson | Tennessee | October 14, 1825 | |
| James DeWolf | Rhode Island | October 31, 1825 | |
| Edward Lloyd | Maryland | January 14, 1826 | |
| James Lloyd | Massachusetts | May 23, 1826 | |
| Henry Harrison | Ohio | May 20, 1828 | |
| Albion Parris | Maine | August 26, 1828 | |
| Thomas Cobb | Georgia | November 7, 1828 | |
| Nathaniel Macon | North Carolina | December 14, 1828 | |
| Ephraim Bateman | New Jersey | January 12, 1829 | |
| Mahlon Dickerson | New Jersey | January 30, 1829 | |
| John Berrien | Georgia | March 9, 1829 | |
| John Branch | North Carolina | March 9, 1829 | |
| John Eaton | Tennessee | March 9, 1829 | |
| Louis McLane | Delaware | April 16, 1829 | |
| Edward Livingston | Louisiana | May 24, 1831 | |
| Issac Barnard | Pennsylvania | December 6, 1831 | |
| Powhatan Ellis | Mississippi | July 16, 1832 | |
| Littleton Tazewell | Virginia | July 16, 1832 | |
| Robert Hayne | South Carolina | December 13, 1832 | |
| William Marcy | New York | January 1, 1833 | |
| George Troup | Georgia | November 8, 1833 | |
| William Rives | Virginia | February 22, 1834 | |
| John Forsyth | Georgia | June 27, 1834 | |
| Ezekiel Chambers | Maryland | December 20, 1834 | |
| Peleg Sprague | Maine | January 1, 1835 | |
| Charles Gayarré | Louisiana | January ??, 1836 | |
| John Tyler | Virginia | February 29, 1836 | |
| Ether Shepley | Maine | March 3, 1836 | |
| Willie Mangum | North Carolina | March 19, 1836 | |
| Isaac Hill | New Hampshire | May 30, 1836 | |
| Arnold Naudain | Delaware | June 16, 1836 | |
| Benjamin Leigh | Virginia | July 4, 1836 | |
| John Clayton | Delaware | December 29, 1836 | |
| Alexander Porter | Louisiana | January 5, 1837 | |
| Richard Parker | Virginia | March 13, 1837 | |
| John McKinley | Alabama | April 22, 1837 | |
| Pendleton King | Georgia | November 1, 1837 | |
| John Black | Mississippi | January 22, 1838 | |
| Felix Grundy | Tennessee | July 4, 1838 | |
| James F. Trotter | Mississippi | July 10, 1838 | |
| Ephraim Foster | Tennessee | March 3, 1839 | |
| Richard Bayard | Delaware | September 19, 1839 | |
| Lawson White | Tennessee | January 13, 1840 | |
| Robert Strange | North Carolina | November 16, 1840 | |
| Bedford Brown | North Carolina | November 16, 1840 | |
| John Davis | Massachusetts | January 5, 1841 | |
| Daniel Webster | Massachusetts | February 22, 1841 | Resigned to become United States Secretary of State |
| Comer Clay | Alabama | November 15, 1841 | |
| Franklin Pierce | New Hampshire | February 28, 1842 | |
| Alexander Mouton | Louisiana | March 1, 1842 | |
| Henry Clay | Kentucky | March 31, 1842 | |
| Samuel Prentiss | Vermont | April 11, 1842 | |
| Samuel Southard | New Jersey | June 26, 1842 | |
| Reuel Williams | Maine | February 15, 1843 | |
| John Calhoun | South Carolina | March 3, 1843 | |
| William Sprague | Rhode Island | January 17, 1844 | |
| William King | Alabama | April 15, 1844 | |
| Nathaniel Tallmadge | New York | June 17, 1844 | |
| Silas Wright, Jr. | New York | November 26, 1844 | |
| John Berrien | Georgia | March 1, 1845 | |
| Elliot Huger | South Carolina | March 3, 1845 | |
| Levi Woodbury | New Hampshire | September 20, 1845 | |
| William Haywood, Jr. | North Carolina | July 25, 1846 | |
| Walter Colquitt | Georgia | February 4, 1848 | |
| Ambrose Sevier | Arkansas | March 15, 1848 | |
| Lewis Cass | Michigan | May 29, 1848 | |
| John Crittenden | Kentucky | June 12, 1848 | |
| Arthur Bagby | Alabama | June 16, 1848 | |
| John Clayton | Delaware | February 2, 1849 | |
| Reverdy Johnson | Maryland | March 7, 1849 |
1850 to 1899
| Name | State | Party | Date of resignation | Notes |
| Daniel Webster | Massachusetts | Whig | July 22, 1850 | Resigned again to again take office as United States Secretary of State |
| Jefferson Davis | Mississippi | Democratic | September 23, 1851 | Resigned to run for Governor of Mississippi |
| Robert Rhett | South Carolina | Democratic | May 7, 1852 | |
| John Berrien | Georgia | Whig | May 28, 1852 | |
| William R. King | Alabama | Democratic | December 20, 1852 | Resigned to take office as Vice President of the United States |
| Robert Stockton | New Jersey | Democratic | January 10, 1853 | Resigned to serve as president of the Delaware and Raritan Canal Company |
| Solon Borland | Arkansas | Democratic | April 11, 1853 | Resigned on being appointed as United States Minister to Nicaragua |
| Pierre Soulé | Louisiana | Democratic | April 11, 1853 | Resigned on being appointed as United States Minister to Spain |
| Edward Everett | Massachusetts | Whig | June 1, 1854 | Resigned due to ill health |
| Augustus C. Dodge | Iowa | Democratic | February 22, 1855 | Resigned on being appointed as United States Minister to Spain |
| Hannibal Hamlin | Maine | Republican | January 7, 1857 | Resigned to take office as Governor of Maine |
| Asa Biggs | North Carolina | Democratic | May 5, 1858 | Resigned to take office as a judge of the United States District Court for the District of North Carolina |
| Thomas Lanier Clingman | North Carolina | Democratic | May 7, 1858 | |
| Hannibal Hamlin | Maine | Republican | January 17, 1861 | Resigned to take office as Vice President of the United States |
| Jefferson Davis | Mississippi | Democratic | January 21, 1861 | |
| John Slidell | Louisiana | Democratic | February 4, 1861 | |
| Thomas Bragg | North Carolina | Democratic | March 6, 1861 | |
| Salmon P. Chase | Ohio | Republican | March 6, 1861 | Resigned to take office as United States Secretary of the Treasury |
| Andrew Johnson | Tennessee | Democratic | March 4, 1862 | Resigned to take office as Military Governor of Tennessee |
| James F. Simmons | Rhode Island | Republican | August 15, 1862 | Resigned after a case for expulsion for corruption was declined |
| Waitman T. Willey | Virginia | Unionist | March 3, 1863 | |
| James A. Bayard, Jr. | Delaware | Democratic | January 29, 1864 | Resigned in protest of new Senate Loyalty Oath |
| William P. Fessenden | Maine | Republican | July 1, 1864 | Resigned to take office as United States Secretary of the Treasury |
| James Harlan | Iowa | Republican | May 15, 1865 | Resigned to take office as the United States Secretary of the Interior |
| Daniel Clark | New Hampshire | Republican | July 27, 1866 | Resigned to take office as a judge of the United States District Court for the District of New Hampshire |
| James Gurthrie | Kentucky | Democratic | February 7, 1868 | Resigned due to ill health |
| Reverdy Johnson | Maryland | Democratic | July 10, 1868 | |
| James W. Grimes | Iowa | Republican | December 6, 1869 | Resigned due to ill health |
| Charles D. Drake | Missouri | Republican | December 19, 1870 | Resigned to take office as Chief Justice of the United States Court of Claims |
| William Pitt Kellogg | Louisiana | Republican | November 1, 1872 | Resigned to take office as Governor of Louisiana |
| Henry Wilson | Massachusetts | Republican | March 3, 1873 | Resigned to take office as Vice President of the United States |
| Alexander Caldwell | Kansas | Republican | March 24, 1873 | Resigned before a vote could be taken on his expulsion for corruption |
| Eugene Casserly | California | Democratic | November 29, 1873 | |
| Adelbert Ames | Mississippi | Republican | January 4, 1874 | Resigned to take office as Governor of Mississippi |
| Lot M. Morrill | Maine | Republican | July 7, 1876 | Resigned to take office as United States Secretary of the Treasury |
| John Sherman | Ohio | Republican | March 8, 1877 | Resigned to take office as United States Secretary of the Treasury |
| Isaac P. Christiancy | Michigan | Republican | February 10, 1879 | Resigned due to ill health |
| John Brown Gordon | Georgia | Democratic | May 26, 1880 | |
| James G. Blaine | Maine | Republican | March 5, 1881 | Resigned to take office as United States Secretary of State |
| Samuel J. Kirkwood | Iowa | Republican | March 7, 1881 | Resigned to take office as United States Secretary of the Interior |
| William Windom | Minnesota | Republican | March 7, 1881 | Resigned to take office as United States Secretary of the Treasury |
| Roscoe Conkling | New York | Republican | May 16, 1881 | Resigned in protest of the appointment of a New York City customs collector by President James A. Garfield |
| Thomas Platt | New York | Republican | May 16, 1881 | Resigned in support of fellow Senator Conkling's protest |
| Henry M. Teller | Colorado | Republican | April 17, 1882 | Resigned to take office as United States Secretary of the Interior |
| Augustus Hill Garland | Arkansas | Democratic | March 6, 1885 | Resigned to take office as United States Attorney General |
| Thomas F. Bayard | Delaware | Democratic | March 6, 1885 | Resigned to take office as United States Secretary of State |
| Howell Edmunds Jackson | Tennessee | Democratic | April 14, 1886 | Resigned to take office as a judge of the United States Circuit Courts for the Sixth Circuit |
| Jonathan Chace | Rhode Island | Republican | April 9, 1889 | |
| John Henninger Reagan | Texas | Democratic | June 10, 1891 | Resigned to take office as the chairman of the Railroad Commission of Texas |
| John Carlisle | Kentucky | Democratic | February 4, 1893 | Resigned to take office as United States Secretary of the Treasury |
| Edward Douglass White | Louisiana | Democratic | March 12, 1894 | Resigned to take office as an Associate Justice of the Supreme Court of the United States |
| John Sherman | Ohio | Republican | March 4, 1897 | Resigned to take office as United States Secretary of State |
1900 to 1949
| Name | State | Party | Date of resignation | Notes |
| William A. Clark | Montana | Democratic | May 15, 1900 | Resigned before a Senate vote on declaring his election void due to bribery |
| Charles W. Fairbanks | Indiana | Republican | March 3, 1905 | Resigned to take office as Vice President of the United States |
| Joseph Burton | Kansas | Republican | June 4, 1906 | Resigned following corruption charges |
| John Coit Spooner | Wisconsin | Republican | April 30, 1907 | |
| Philander C. Knox | Pennsylvania | Republican | March 4, 1909 | Resigned to take office as United States Secretary of State |
| Fountain L. Thompson | North Dakota | Democratic | January 31, 1910 | |
| Joseph M. Terrell | Georgia | Democratic | July 14, 1911 | Resigned for health reasons |
| Joseph Weldon Bailey | Texas | Democratic | January 3, 1913 | |
| Warren G. Harding | Ohio | Republican | January 13, 1921 | First President of the United States to be elected during his term as a Senator |
| John F. Nugent | Idaho | Democratic | January 14, 1921 | Resigned to take office as a member of the Federal Trade Commission |
| Albert B. Fall | New Mexico | Republican | March 4, 1921 | Resigned to take office as United States Secretary of the Interior |
| Josiah O. Wolcott | Delaware | Democratic | July 2, 1921 | Resigned to take office as Chancellor of Delaware |
| William Kenyon | Iowa | Republican | February 24, 1922 | Resigned to take office as a federal judge on the United States Court of Appeals for the 8th Circuit |
| Truman Newberry | Michigan | Republican | November 18, 1922 | Resigned after being condemned for violating campaign financing rules |
| Frank L. Smith | Illinois | Republican | February 9, 1928 | Resigned after the Senate voted to refuse to seat him due to fraud and corruption |
| T. Coleman du Pont | Delaware | Republican | December 8, 1928 | Resigned to allow early appointment of successor |
| Charles Curtis | Kansas | Republican | March 3, 1929 | Resigned to take office as Vice President of the United States |
| Evans Edge | New Jersey | Republican | November 21, 1929 | Resigned to take office as United States Ambassador to France |
| Frederic M. Sackett | Kentucky | Republican | January 9, 1930 | Resigned to take office as United States Ambassador to Germany |
| Cordell Hull | Tennessee | Democratic | March 3, 1933 | Resigned to take office as United States Secretary of State |
| Claude A. Swanson | Virginia | Democratic | March 3, 1933 | Resigned to take office as United States Secretary of the Navy |
| Sam G. Bratton | New Mexico | Democratic | June 24, 1933 | Resigned to take office as a federal judge on the United States Court of Appeals for the 10th Circuit |
| Hugo Black | Alabama | Democratic | August 19, 1937 | Resigned to take office as an Associate Justice of the United States Supreme Court |
| Dixie Bibb Graves | Alabama | Democratic | January 10, 1938 | |
| Harry Moore | New Jersey | Democratic | January 17, 1938 | Resigned to take office as Governor of New Jersey |
| Frederick Steiwer | Oregon | Republican | January 31, 1938 | |
| William Gibbs McAdoo | California | Democratic | November 8, 1938 | |
| Matthew M. Neely | West Virginia | Democratic | January 12, 1941 | Resigned to take office as Governor of West Virginia |
| John E. Miller | Arkansas | Democratic | March 31, 1941 | Resigned to take office as a federal judge on the District Court for the Western District of Arkansas |
| James Byrnes | South Carolina | Democratic | July 8, 1941 | Resigned to take office as an Associate Justice of the United States Supreme Court |
| Henry Cabot Lodge, Jr. | Massachusetts | Republican | February 3, 1944 | Resigned to return to active duty in the United States Army during the Second World War |
| Homer Bone | Washington | Democratic | November 13, 1944 | Resigned to take office as Judge on the United States Court of Appeals for the Ninth Circuit. |
| Sinclair Weeks | Massachusetts | Republican | December 19, 1944 | |
| Monrad Wallgren | Washington | Democratic | January 9, 1945 | Resigned to take office as Governor of Washington |
| Harry Truman | Missouri | Democratic | January 17, 1945 | Resigned to take office as Vice President of the United States |
| Harold Burton | Ohio | Republican | September 30, 1945 | Resigned to take office as an Associate Justice of the United States Supreme Court |
| Happy Chandler | Kentucky | Democratic | November 1, 1945 | Resigned to become Commissioner of Baseball |
| Warren Austin | Vermont | Republican | August 2, 1946 | Resigned to take office as the United States Ambassador to the United Nations |
| Hugh Mitchell | Washington | Democratic | December 25, 1946 | Resigned to allow early appointment of successor |
| Vera Bushfield | South Dakota | Republican | December 26, 1948 | Resigned to allow early appointment of successor |
| Alben Barkley | Kentucky | Democratic | January 19, 1949 | Resigned to take office as Vice President of the United States |
| Robert Wagner | New York | Democratic | June 28, 1949 | Resigned due to health reasons |
| Howard McGrath | Rhode Island | Democratic | August 23, 1949 | Resigned to take office as United States Attorney General |
| Raymond Baldwin | Connecticut | Republican | December 16, 1949 | Resigned to take office as an associate justice on the Connecticut Supreme Court of Errors |