Longest Serving Senators

These 25 individuals have served the longest U.S. Senate terms as of July 29, 2014.

Senator

Dates of Service

Length of Service

1. Robert C. Byrd (D-WV)

Jan 3, 1959 to Jun 28, 2010

51 years, 5 months, 26 days

2. Daniel K. Inouye (D-HI)

Jan 3, 1963 to Dec 17, 2012

49 years, 11 months, 15 days

3. Strom Thurmond (R-SC)

Dec 14, 1954 to Apr 4, 1956
and Nov 7, 1956 to Jan 3, 2003

47 years, 5 months, 8 days

4. Edward M. Kennedy (D-MA)

Nov 7, 1962 to Aug 25, 2009

46 years, 9 months, 19 days

5. Carl T. Hayden (D-AZ)

Mar 4, 1927 to Jan 3, 1969

41 years, 9 months, 30 days

6. John Stennis (D-MS)

Nov 5, 1947 to Jan 3, 1989

41 years, 1 month, 29 days

7. Ted Stevens (R-AK)

Dec 24, 1968 to Jan 3, 2009

40 years, 10 days

8. Patrick J. Leahy (D-VT)

Jan 3, 1975 to present

39 years, 6 months, 27 days

9. Ernest F. Hollings (D-SC)

Nov 9, 1966 to Jan 3, 2005

38 years, 1 month, 25 days

10. Richard B. Russell (D-GA)

Jan 12, 1933 to Jan 21, 1971

38 years, 10 days

11. Russell Long (D-LA)

Dec 31, 1948 to Jan 3, 1987

38 years, 3 days

12. Orrin Hatch (R-UT)

Jan 3, 1977 to present

37 years, 6 months, 27 days

13. Francis E. Warren (R-WY)

Nov 18, 1890 to Mar 3, 1893
and Mar 4, 1895 to Nov 24, 1929

37 years, 4 days

14. James Eastland (D-MS)

Jun 30, 1941 to Sep 28, 1941
and Jan 3, 1943 to Dec 27, 1978

36 years, 2 months, 24 days

15. Warren Magnuson (D-WA)

Dec 14, 1944 to Jan 3, 1981

36 years, 20 days

16. Joseph R. Biden, Jr. (D-DE)

Jan 3, 1973 to Jan 15, 2009

36 years, 13 days

17. Pete V. Domenici (R-NM)

Jan 3, 1973 to Jan 3, 2009

36 years

17. Richard Lugar (R-IN)

Jan 3, 1977 to Jan 3, 2013

36 years

17. Claiborne Pell (D-RI)

Jan 3, 1961 to Jan 3, 1997

36 years

20. Kenneth D. McKellar (D-TN)

Mar 4, 1917 to Jan 3, 1953

35 years, 10 months

21. Milton R. Young (R-ND)

Mar 12, 1945 to Jan 3, 1981

35 years, 9 months, 22 days

22. Ellison D. Smith (D-SC)

Mar 4, 1909 to Nov 17, 1944

35 years, 8 months, 13 days

23. Thad Cochran (R-MS)

Dec 27, 1978 to present

35 years, 7 months, 3 days

24. Carl Levin (D-MI)

Jan 3, 1979 to present

35 years, 6 months, 27 days

25. Allen Joseph Ellender (D-LA)

Jan 3, 1937 to Jul 27, 1972

35 years, 6 months, 24 days