Earliest serving United States Senator Earliest serving Senators currently living Earliest serving Senators currently living

| Rank_ | Senator | Date_of_birth | Entered_Senate | Left_Senate | State_served | Party | Time_since_entry |
|---|---|---|---|---|---|---|---|
| 1 | Birch Bayh | January 22, 1928 | January 3, 1963 | January 3, 1981 | Indiana | Democrat | 51years, 29days |
| 2 | Fred R. Harris | November 13, 1930 | November 4, 1964 | January 3, 1973 | Oklahoma | Democrat | 49years, 89days |
| 3 | Walter Mondale | January 5, 1928 | December 30, 1964 | December 30, 1976 | Minnesota | Democrat | 49years, 33days |
| 4 | Joseph Tydings | May 4, 1928 | January 3, 1965 | January 3, 1971 | Maryland | Democrat | 49years, 29days |
| 5 | Robert P. Griffin | November 6, 1923 | May 11, 1966 | January 2, 1979 | Michigan | Republican | 47years, 266days |
| 6 | Ernest Hollings | January 1, 1922 | November 9, 1966 | January 3, 2005 | South Carolina | Democrat | 47years, 84days |