U
| Senator | Years | State | Party |
|---|---|---|---|
| William B. Umstead | 1946–1948 | North Carolina | Democratic |
| Joseph R. Underwood | 1847–1853 | Kentucky | Whig |
| Oscar Underwood | 1915–1927 | Alabama | Democratic |
| Thomas R. Underwood | 1951–1952 | Kentucky | Democratic |
| William Upham | 1843–1853 | Vermont | Whig |
| Robert W. Upton | 1953–1954 | New Hampshire | Republican |
Read more about this topic: List Of Former United States Senators