This is a classification of United States Senators by seniority from January 3, 2011 to January 2013. It is a historical listing and will contain people who have not served the entire two-year Congress should anyone resign, die, or be expelled.
Order of service is based on the commencement of the senator's first term. Behind this is former service as a senator (only giving the senator seniority within his or her new incoming class), service as Vice President, a House member, a Cabinet secretary, or a governor of a state. The final factor is the population of the senator's state.[1][2][3][4][5]
Senators who were sworn in in the middle of the two-year Congress (up until the last senator who was not sworn in early after winning the November 2012 election) are listed at the end of the list with no number.
In the 112th Congress, Tom Harkin is the most senior junior senator, and Jeanne Shaheen is the most junior senior senator.
| Rank | Name | Seniority date | Other factors |
|---|---|---|---|
| 1 | Daniel Inouye (D-HI) | January 3, 1963 | |
| 2 | Patrick Leahy (D-VT) | January 3, 1975 | |
| 3 | Richard Lugar (R-IN) | January 3, 1977 | Indiana 11th in population (1970) |
| 4 | Orrin Hatch (R-UT) | Utah 36th in population (1970) | |
| 5 | Max Baucus (D-MT) | December 15, 1978 | |
| 6 | Thad Cochran (R-MS) | December 27, 1978 | |
| 7 | Carl Levin (D-MI) | January 3, 1979 | |
| 8 | Chuck Grassley (R-IA) | January 3, 1981 | Former U.S. representative (6 years); Iowa 25th in population (1970) |
| 9 | Jeff Bingaman (D-NM) | January 3, 1983 | |
| 10 | John Kerry (D-MA) | January 2, 1985 | |
| 11 | Tom Harkin (D-IA) | January 3, 1985 | Former U.S. representative |
| 12 | Mitch McConnell (R-KY) | ||
| 13 | Jay Rockefeller (D-WV) | January 15, 1985 | |
| 14 | Barbara Mikulski (D-MD) | January 3, 1987 | Former U.S. representative (10 years) |
| 15 | Richard Shelby (R-AL) | Former U.S. representative (8 years) | |
| 16 | John McCain (R-AZ) | Former U.S. representative (4 years); Arizona 29th in population (1980) | |
| 17 | Harry Reid (D-NV) | Former U.S. representative (4 years); Nevada 43rd in population (1980) | |
| 18 | Kent Conrad (D-ND) | ||
| 19 | Herb Kohl (D-WI) | January 3, 1989 | Wisconsin 16th in population (1980) |
| 20 | Joe Lieberman (ID-CT)[6] | Connecticut 25th in population (1980) | |
| 21 | Daniel Akaka (D-HI) | May 16, 1990 | |
| 22 | Dianne Feinstein (D-CA) | November 10, 1992 | |
| 23 | Barbara Boxer (D-CA) | January 3, 1993 | Former U.S. representative |
| 24 | Patty Murray (D-WA) | ||
| 25 | Kay Bailey Hutchison (R-TX) | June 14, 1993 | |
| 26 | Jim Inhofe (R-OK) | November 17, 1994 | |
| 27 | Olympia Snowe (R-ME) | January 3, 1995 | Former U.S. representative (16 years) |
| 28 | Jon Kyl (R-AZ) | Former U.S. representative (8 years) | |
| 29 | Ron Wyden (D-OR) | February 6, 1996 | |
| 30 | Pat Roberts (R-KS) | January 3, 1997 | Former U.S. representative (16 years) |
| 31 | Richard Durbin (D-IL) | Former U.S. representative (14 years) | |
| 32 | Tim Johnson (D-SD) | Former U.S. representative (10 years) | |
| 33 | Jack Reed (D-RI) | Former U.S. representative (6 years) | |
| 34 | Mary Landrieu (D-LA) | Louisiana 21st in population (1990) | |
| 35 | Jeff Sessions (R-AL) | Alabama 22nd in population (1990) | |
| 36 | Susan Collins (R-ME) | Maine 38th in population (1990) | |
| 37 | Mike Enzi (R-WY) | Wyoming 50th in population (1990) | |
| 38 | Chuck Schumer (D-NY) | January 3, 1999 | Former U.S. representative (18 years) |
| 39 | Mike Crapo (R-ID) | Former U.S. representative (6 years) | |
| 40 | Bill Nelson (D-FL) | January 3, 2001 | Former U.S. representative (12 years) |
| 41 | Tom Carper (D-DE) | Former U.S. representative (10 years) | |
| 42 | Debbie Stabenow (D-MI) | Former U.S. representative (4 years); Michigan 8th in population (1990) | |
| 43 | John Ensign (R-NV) | Former U.S. representative (4 years); Nevada 39th in population (1990) | |
| 44 | Maria Cantwell (D-WA) | Former U.S. representative (2 years) | |
| 45 | Ben Nelson (D-NE) | ||
| 46 | Lisa Murkowski | December 20, 2002 | |
| 47 | Frank Lautenberg[7] (D-NJ) | January 3, 2003 | Former senator |
| 48 | Saxby Chambliss (R-GA) | Former U.S. representative (8 years); Georgia 10th in population (2000) | |
| 49 | Lindsey Graham (R-SC) | Former U.S. representative (8 years); South Carolina 26th in population (2000) | |
| 50 | Lamar Alexander (R-TN) | Former Cabinet member | |
| 51 | John Cornyn[8] (R-TX) | Texas 2nd in population (2000) | |
| 52 | Mark Pryor (D-AR) | Arkansas 33nd in population (2000) | |
| 53 | Richard Burr (R-NC) | January 3, 2005 | Former U.S. representative (10 years) |
| 54 | Jim DeMint (R-SC) | Former U.S. representative (6 years); South Carolina 26th in population (2000) | |
| 55 | Tom Coburn (R-OK) | Former U.S. representative (6 years); Oklahoma 27th in population (2000) | |
| 56 | John Thune (R-SD) | Former U.S. representative (6 years); South Dakota 46th in population (2000) | |
| 57 | Johnny Isakson (R-GA) | Former U.S. representative (5 years, 10 months) | |
| 58 | David Vitter (R-LA) | Former U.S. representative (5 years, 7 months) | |
| 59 | Bob Menendez (D-NJ) | January 18, 2006 | |
| 60 | Ben Cardin (D-MD) | January 3, 2007 | Former U.S. representative (20 years) |
| 61 | Bernie Sanders (I-VT) | Former U.S. representative (16 years) | |
| 62 | Sherrod Brown (D-OH) | Former U.S. representative (14 years) | |
| 63 | Bob Casey, Jr. (D-PA) | Pennsylvania 6th in population (2000) | |
| 64 | Jim Webb[9] (D-VA) | Virginia 12th in population (2000) | |
| 65 | Bob Corker (R-TN) | Tennessee 16th in population (2000) | |
| 66 | Claire McCaskill (D-MO) | Missouri 17th in population (2000) | |
| 67 | Amy Klobuchar (D-MN) | Minnesota 21st in population (2000) | |
| 68 | Sheldon Whitehouse (D-RI) | Rhode Island 43rd in population (2000) | |
| 69 | Jon Tester (D-MT) | Montana 44th in population (2000) | |
| 70 | John Barrasso (R-WY) | June 25, 2007 | |
| 71 | Roger Wicker (R-MS) | December 31, 2007 | |
| 72 | Mark Udall (D-CO) | January 3, 2009 | Former U.S. representative (10 years); Colorado 24th in population (2000) |
| 73 | Tom Udall (D-NM) | Former U.S. representative (10 years); New Mexico 36th in population (2000) | |
| 74 | Mike Johanns (R-NE) | Former Cabinet member | |
| 75 | Jeanne Shaheen (D-NH) | Former governor (6 years) | |
| 76 | Mark Warner (D-VA) | Former governor (4 years) | |
| 77 | Jim Risch (R-ID) | Former governor (7 months) | |
| 78 | Kay Hagan (D-NC) | North Carolina 11th in population (2000) | |
| 79 | Jeff Merkley (D-OR) | Oregon 28th in population (2000) | |
| 80 | Mark Begich (D-AK) | Alaska 48th in population (2000) | |
| 81 | Michael Bennet (D-CO) | January 21, 2009 | |
| 82 | Kirsten Gillibrand (D-NY) | January 26, 2009 | |
| 83 | Al Franken (D-MN) | July 7, 2009 | |
| 84 | Scott Brown (R-MA) | February 4, 2010 | |
| 85 | Mark Kirk (R-IL) | November 15, 2010 | Former U.S. representative |
| 86 | Joe Manchin (D-WV) | November 15, 2010 | Former governor |
| 87 | Chris Coons (-DE) | November 15, 2010 | Delaware 45th in population (2000) |
| 88 | Dan Coats (R-IN) | January 3, 2011 | Former senator |
| 89 | Roy Blunt (R-MO) | Former U.S. representative (14 years); Missouri 17th in population (2000) | |
| 90 | Jerry Moran (R-KS) | Former U.S. representative (14 years); Kansas 32nd in population (2000) | |
| 91 | Rob Portman (R-OH) | Former U.S. representative (12 years) | |
| 92 | John Boozman (R-AR) | Former U.S. Representative (9 years) | |
| 93 | Pat Toomey (R-PA) | Former U.S. Representative (6 years) | |
| 94 | John Hoeven (R-ND) | Former governor | |
| 95 | Marco Rubio (R-FL) | Florida 4th in population (2000) | |
| 96 | Ron Johnson (R-WI) | Wisconsin 18th in population (2002) | |
| 97 | Rand Paul (R-KY) | Kentucky 25th in population (2000) | |
| 98 | Richard Blumenthal (D-CT) | Connecticut 29th in population (2000) | |
| 99 | Michael S. Lee (R-UT) | Utah 34th in population (2000) | |
| 100 | Kelly Ayotte (R-NH) | New Hampshire 41st in population (2000) | |
| Dean Heller (R-NV) | May 9, 2011 |
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