Senate rank is first determined by the length of consecutive service in the Senate. For senators who entered the Senate on the same day, several tie-breaking procedures determine seniority. In order of precedence, these factors are: previous Senate service, service as the vice president, previous House service; service in the Cabinet, service as a state governor. If a tie still exists, senators are ranked according to the population of their state at the time of swearing in.

Rank

All 100 Senators

Date Service Began

1.	Patrick J. Leahy, D-Vt.	Jan. 3, 1975
2.	Orrin G. Hatch, R-Utah	Jan. 3, 1977
3.	Max Baucus, D-Mont.	Dec. 15, 1978
4.	Thad Cochran, R-Miss.	Dec. 27, 1978
5.	Carl Levin, D-Mich.	Jan. 3, 1979
6.	Charles E. Grassley, R-Iowa	Jan. 3, 1981
7.	Tom Harkin, D-Iowa	Jan. 3, 1985
8.	Mitch McConnell, R-Ky.	Jan. 3, 1985
9.	John D. Rockefeller IV, D-W.Va.	Jan. 15, 1985
10.	Barbara A. Mikulski, D-Md.	Jan. 3, 1987
11.	Richard C. Shelby, R-Ala.	Jan. 3, 1987
12.	John McCain, R-Ariz.	Jan. 3, 1987
13.	Harry Reid, D-Nev.	Jan. 3, 1987
14.	Dianne Feinstein, D-Calif.	Nov. 10, 1992
15.	Barbara Boxer, D-Calif.	Jan. 3, 1993
16.	Patty Murray, D-Wash.	Jan. 3, 1993
17.	James M. Inhofe, R-Okla.	Nov. 16, 1994
18.	Ron Wyden, D-Ore.	Feb. 6, 1996
19.	Pat Roberts, R-Kan.	Jan. 7, 1997
20.	Richard J. Durbin, D-Ill.	Jan. 7, 1997
21.	Tim Johnson, D-S.D.	Jan. 7, 1997
22.	Jack Reed, D-R.I.	Jan. 7, 1997
23.	Mary L. Landrieu, D-La.	Jan. 7, 1997
24.	Jeff Sessions, R-Ala.	Jan. 7, 1997
25.	Susan Collins, R-Maine	Jan. 7, 1997
26.	Michael B. Enzi, R-Wyo.	Jan. 7, 1997
27.	Charles E. Schumer, D-N.Y.	Jan. 6, 1999
28.	Michael D. Crapo, R-Idaho	Jan. 6, 1999
29.	Bill Nelson, D-Fla.	Jan. 3, 2001
30.	Thomas R. Carper, D-Del.	Jan. 3, 2001
31.	Debbie Stabenow, D-Mich.	Jan. 3, 2001
32.	Maria Cantwell, D-Wash.	Jan. 3, 2001
33.	Lisa Murkowski, R-Alaska	Dec. 20, 2002
34.	Saxby Chambliss, R-Ga.	Jan. 7, 2003
35.	Lindsey Graham, R-S.C.	Jan. 7, 2003
36.	Lamar Alexander, R-Tenn.	Jan. 7, 2003
37.	John Cornyn, R-Texas	Dec. 2, 2002*
38.	Mark Pryor, D-Ark.	Jan. 7, 2003
39.	Richard M. Burr, R-N.C.	Jan. 3, 2005
40.	Tom Coburn, R-Okla.	Jan. 3, 2005
41.	John Thune, R-S.D.	Jan. 3, 2005
42.	Johnny Isakson, R-Ga.	Jan. 3, 2005
43.	David Vitter, R-La.	Jan. 3, 2005
44.	Robert Menendez, D-N.J.	Jan. 18, 2006
45.	Benjamin L. Cardin, D-Md.	Jan. 4, 2007
46.	Bernie Sanders, I-Vt.	Jan. 4, 2007
47.	Sherrod Brown, D-Ohio	Jan. 4, 2007
48.	Bob Casey, D-Pa.	Jan. 4, 2007
49.	Bob Corker, R-Tenn.	Jan. 4, 2007
50.	Claire McCaskill, Mo.	Jan. 4, 2007
51.	Amy Klobuchar, Minn.	Jan. 4, 2007
52.	Sheldon Whitehouse, R.I.	Jan. 4, 2007
53.	Jon Tester, Mont.	Jan. 4, 2007
54.	John A. Barrasso, R-Wyo.	June 22, 2007
55.	Roger Wicker, R-Miss.	Dec. 31, 2007
56.	Mark Udall, D-Colo.	Jan. 6, 2009
57.	Tom Udall, D-N.M.	Jan. 6, 2009
58.	Mike Johanns, R-Neb.	Jan. 6, 2009
59.	Jeanne Shaheen, D-N.H.	Jan. 6, 2009
60.	Mark Warner, D-Va.	Jan. 6, 2009
61.	Jim Risch, R-Idaho	Jan. 6, 2009
62.	Kay Hagan, D-N.C.	Jan. 6, 2009
63.	Jeff Merkley, D-Ore.	Jan. 6, 2009
64.	Mark Begich, D-Alaska	Jan. 6, 2009
65.	Michael Bennet, D-Colo.	Jan. 22, 2009
66.	Kirsten Gillibrand, D-N.Y.	Jan. 27, 2009
67.	Al Franken, D-Minn.	Jul. 7, 2009
68.	Joe Manchin, D-W. Va.	Nov. 15, 2010
69.	Chris Coons, D-Del.	Nov. 15, 2010
70.	Mark Kirk, R-Ill.	Nov. 29, 2010
71.	Dan Coats, R-Ind.	Jan. 3, 2011
72.	Roy Blunt, R-Mo.	Jan. 3, 2011
73.	Jerry Moran, R-Kan.	Jan. 3, 2011
74.	Rob Portman, R-Ohio	Jan. 3, 2011
75.	John Boozman, R-Ark.	Jan. 3, 2011
76.	Pat Toomey, R-Pa.	Jan. 3, 2011
77.	John Hoeven, R-N.D.	Jan. 3, 2011
78.	Marco Rubio, R-Fla.	Jan. 3, 2011
79.	Ron Johnson, R-Wis.	Jan. 3, 2011
80.	Rand Paul, R-Ky.	Jan. 3, 2011
81.	Richard Blumenthal, D-Conn.	Jan. 3, 2011
82.	Mike Lee, R-Utah.	Jan. 3, 2011
83.	Kelly Ayotte, R-N.H.	Jan. 3, 2011
84.	Dean Heller, R-Nev.	May 9, 2011
85.	Brian Schatz, D-Hawaii.	Dec. 27, 2012
86.	Tim Scott, R-S.C.	Jan. 3, 2013
87.	Tammy Baldwin, D-Wis.	Jan. 3, 2013
88.	Jeff Flake, R-AZ	Jan. 3, 2013
89.	Joe Donnelly, D-Ind.	Jan. 3, 2013
90.	Chris Murphy, D-Conn.	Jan. 3, 2013
91.	Mazie Hirono, D-Hawaii.	Jan. 3, 2013
92.	Martin Heinrich, D-N.M.	Jan. 3, 2013
93.	Angus King (I-ME)	Jan. 3, 2013
94.	Tim Kaine, D-Va.	Jan. 3, 2013
95.	Ted Cruz, R-TX	Jan. 3, 2013
96.	Elizabeth Warren, D-MA	Jan. 3, 2013
97.	Deb Fischer, R-NE	Jan. 3, 2013
98.	Heidi Heitkamp, D-N.D.	Jan. 3, 2013
99.	William “Mo” Cowan, D-Mass.	Feb. 1, 2013
100.	Jeff Chiesa, R-N.J.	Jun. 10, 2013

* Phil Gramm resigned early, effective Nov. 30, 2002, so that Cornyn could move into his office suite and begin organizing his staff. Cornyn did not, however, gain seniority, owing to a 1980 Rules Committee policy established by Senator Pell that no longer gave seniority to senators who entered Congress early for the purpose of gaining advantageous office space.