Source

From 1789 to 1958, senators whose terms began on the same day are listed alphabetically. Beginning in 1959, senators are listed according to commencement of first Senate term by order of service, determined by former service in order as senator, vice president, House member, cabinet secretary, governor, and then by state population. This latter system for calculating order of service has been used by the modern Senate for many years for the purposes of office assignment. It is unclear just when the Senate first began applying such criteria.

  1. Patrick Leahy, D-Vermont, January 3, 1975
  2. Charles Grassley, R-Iowa, January 3, 1981
  3. Mitch McConnell, R-Kentucky, January 3, 1985
  4. Richard Shelby, R-Alabama, January 3, 1987
  5. Dianne Feinstein, D-California, November 4, 1992
  6. Patty Murray, D-Washington, January 3, 1993
  7. James Inhofe, R-Oklahoma, November 16, 1994
  8. Ron Wyden, D-Oregon, February 6, 1996
  9. Richard Durbin, D-Illinois, January 3, 1997
  10. Jack Reed, D-Rhode Island, January 3,1997
  11. Susan Collins, R-Maine, January 3, 1997
  12. Chuck Schumer, D-New York, January 3, 1999
  13. Michael Crapo, R-Idaho, January 3, 1999
  14. Thomas Carper, D-Delaware, January 3, 2001
  15. Debbie Stabenow, D-Michigan, January 3, 2001
  16. Maria Cantwell, D-Washington, January 3, 2001
  17. Lisa Murkowski, R-Alaska, December 20, 2002
  18. Lindsey Graham, R-South Carolina, January 3, 2003
  19. John Cornyn, R-Texas, December 2, 2002
  20. Richard M. Burr, R-North Carolina, January 3, 2005
  21. John Thune, R-South Dakota, January 3, 2005
  22. Robert Menendez, D-New Jersey, January 18, 2006
  23. Benjamin L. Cardin, D-Maryland, January 3, 2007
  24. Bernie Sanders, I-Vermont, January 3, 2007
  25. Sherrod Brown, D-Ohio, January 3, 2007
  26. Bob Casey, D-Pennsylvania, January 3, 2007
  27. Amy Klobuchar, D-Minnesota, January 3, 2007
  28. Sheldon Whitehouse, D-Rhode Island, January 3, 2007
  29. Jon Tester, D-Montana, January 3, 2007
  30. John A. Barrasso, R-Wyoming, June 22, 2007
  31. Roger Wicker, R-Mississippi, December 31, 2007
  32. Jeanne Shaheen, D-New Hampshire, January 3, 2009
  33. Mark Warner, D-Virginia, January 3, 2009
  34. Jim Risch, R-Idaho, January 3, 2009
  35. Jeff Merkley, D-Oregon, January 3, 2009
  36. Michael Bennet, D-Colorado, January 22, 2009
  37. Kirsten Gillibrand, D-New York, January 27, 2009
  38. Joe Manchin, D-West Virginia, November 15, 2010
  39. Chris Coons, D-Delaware, November 15, 2010
  40. Roy Blunt, R-Missouri, January 3, 2011
  41. Jerry Moran, R-Kansas, January 3, 2011
  42. Rob Portman, R-Ohio, January 3, 2011
  43. John Boozman, R-Arkansas, January 3, 2011
  44. Pat Toomey, R-Pennsylvania, January 3, 2011
  45. John Hoeven, R-North Dakota, January 3, 2011
  46. Marco Rubio, R-Florida, January 3, 2011
  47. Ron Johnson, R-Wisconsin, January 3, 2011
  48. Rand Paul, R-Kentucky, January 3, 2011
  49. Richard Blumenthal, D-Connecticut, January 3, 2011
  50. Mike Lee, R-Utah, January 3, 2011
  51. Brian Schatz, D-Hawaii, December 27, 2012
  52. Tim Scott, R-South Carolina, January 3, 2013
  53. Tammy Baldwin, D-Wisconsin, January 3, 2013
  54. Chris Murphy, D-Connecticut, January 3, 2013
  55. Mazie Hirono, D-Hawaii, January 3, 2013
  56. Martin Heinrich, D-New Mexico, January 3, 2013
  57. Angus King, I-Maine, January 3, 2013
  58. Tim Kaine, D-Virginia, January 3, 2013
  59. Ted Cruz, R-Texas, January 3, 2013
  60. Elizabeth Warren, D-Massachusetts, January 3, 2013
  61. Deb Fischer, R-Nebraska, January 3, 2013
  62. Edward Markey, D-Massachusetts, July 16, 2013
  63. Cory Booker, D-New Jersey, October 31, 2013
  64. Shelley Moore Capito, R-West Virginia, January 3, 2015
  65. Gary Peters, D-Michigan, January 3, 2015
  66. Bill Cassidy, R-Louisiana, January 3, 2015
  67. James Lankford, R-Oklahoma, January 3, 2015
  68. Tom Cotton, R-Arkansas, January 3, 2015
  69. Steve Daines, R-Montana, January 3, 2015
  70. Mike Rounds, R-South Dakota, January 3, 2015
  71. Thom Tillis, R-North Carolina, January 3, 2015
  72. Joni Ernst, R-Iowa, January 3, 2015
  73. Ben Sasse, R-Nebraska, January 3, 2015
  74. Dan Sullivan, R-Alaska, January 3, 2015
  75. Chris Van Hollen, D-Maryland, January 3, 2017
  76. Todd Young, R-Indiana, January 3, 2017
  77. Tammy Duckworth, D-Illinois, January 3, 2017
  78. Maggie Hassan, D-New Hampshire, January 3, 2017
  79. John Kennedy, R-Louisiana, January 3, 2017
  80. Catherine Cortez-Masto, D-Nevada, January 3, 2017
  81. Tina Smith, D-Minnesota, January 3, 2018
  82. Cindy Hyde Smith, R-Mississippi, April 9, 2018
  83. Marsha Blackburn, R-Tennessee, January 3, 2019
  84. Kyrsten Sinema, D-Arizona, January 3, 2019
  85. Kevin Cramer, R-North Dakota, January 3, 2019
  86. Jacky Rosen, D-Nevada, January 3, 2019
  87. Mitt Romney, R-Utah, January 3, 2019
  88. Mike Braun, R-Indiana, January 3, 2019
  89. Josh Hawley, R-Missouri, January 3, 2019
  90. Rick Scott, R-Florida, January 8, 2019
  91. Mark Kelly, D-Arizona, December 2, 2020
  92. Ben Ray Lujan, D-New Mexico, January 3, 2021
  93. Cynthia Loomis, R-Wyoming, January 3, 2021
  94. Roger Marshall, R-Kansas, January 3, 2021
  95. John Hickenlooper, D-Colorado, January 3, 2021
  96. Bill Hagerty, R-Tennessee, January 3, 2021
  97. Tommy Tuberville, R-Alabama, January 3, 2021
  98. Alex Padilla, D-California, January 20, 2021
  99. Jon Ossoff, D-Georgia, January 20, 2021
  100. Raphael Warnock D-Georgia, January 20, 2021