# List of United States senators in the 21st Congress

This is a complete list of members of the United States Senate during the 21st United States Congress listed by seniority, from March 4, 1829, to March 3, 1831.
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.
Senators who were sworn in during the middle of the two-year congressional term (up until the last senator who was not sworn in early after winning the November 1830 election) are listed at the end of the list with no number.

## Terms of service

| Class | Terms of service of senators that expired in years |
| Class 3 | Terms of service of senators that expired in 1831 (AL, CT, GA, IL, IN, KY, LA, MD, MO, NC, NH, NY, OH, PA, SC, and VT.) |
| Class 1 | Terms of service of senators that expired in 1833 (CT, DE, IN, MA, MD, ME, MO, MS, NJ, NY, OH, PA, RI, TN, VA, and VT.) |
| Class 2 | Terms of service of senators that expired in 1835 (AL, DE, GA, IL, KY, LA, MA, ME, MS, NC, NH, NJ, RI, SC, TN, and VA.) |

## U.S. Senate seniority list

U.S. Senate seniority :
| Rank | Senator (party-state) | Seniority date | Other factors |
| 1 | Benjamin Ruggles (AJ-OH) | March 4, 1815 | |
| 2 | James Noble (AJ-IN) | December 11, 1816 |
| 3 | Mahlon Dickerson (J-NJ) | March 4, 1817 |
| 4 | William Rufus de Vane King (J-AL) | December 14, 1819 |
| 5 | Nehemiah Rice Knight (AJ-RI) | January 9, 1821 |
| 6 | Horatio Seymour (AJ-VT) | March 4, 1821 | Vermont 15th in population (1810) |
| 7 | David Barton (AJ-MO) | August 10, 1821 | Alphabetical (Ba) |
| 8 | Thomas Hart Benton (J-MO) | August 10, 1821 | Alphabetical (Be) |
| 9 | John Henry Eaton (J-TN) | September 27, 1821 |
| 10 | Samuel Smith (J-MD) | December 17, 1822 |
| 11 | Samuel Bell (AJ-NH) | March 4, 1823 | Former governor; New Hampshire 15th in population (1820) |
| 12 | Robert Young Hayne (J-NH) | March 4, 1823 |
| 13 | Josiah Stoddard Johnston (AJ-LA) | January 15, 1824 |
| 14 | Littleton Waller Tazewell (J-VA) | December 7, 1824 |
| 15 | Dudley Chase (AJ-VT) | March 4, 1825 | Former senator |
| 16 | William Hendricks (AJ-IN) | March 4, 1825 | Former representative (5 years) |
| 17 | John Rowan (J-KY) | March 4, 1825 | Former representative (2 years) |
| 18 | William Marks (AJ-PA) | March 4, 1825 | Pennsylvania 2nd in population (1820) |
| 19 | John Macpherson Berrien (J-GA) | March 4, 1825 | Georgia 11th in population (1820) |
| 20 | Elias Kent Kane (J-IL) | March 4, 1825 | Illinois 24th in population (1820) |
| 21 | Levi Woodbury (J-NH) | March 16, 1825 |
| 22 | Calvin Willey (AJ-CT) | May 4, 1825 |
| 23 | Hugh Lawson White (J-TN) | October 28, 1825 |
| 24 | Ashur Robbins (AJ-RI) | October 31, 1825 |
| 25 | Nathan Sanford (AJ-NY) | January 14, 1826 |
| 26 | Ezekiel Forman Chambers (AJ-VA) | January 24, 1826 |
| 27 | Nathaniel Silsbee (AJ-MA) | May 31, 1826 |
| 28 | John McKinley (J-AL) | November 27, 1826 |
| 29 | William Smith (DR-SC) | November 29, 1826 |
| 30 | Powhatan Ellis (J-MS) | March 4, 1827 | Former senator |
| 31 | Louis McLane (J-DE) | March 4, 1827 | Former representative (10 years) |
| 32 | John Tyler (J-VA) | March 4, 1827 | Former representative (4 years, 2 months) |
| 33 | Samuel Augustus Foot (AJ-CT) | March 4, 1827 | Former representative (4 years, 0 months) |
| 34 | Isaac Dutton Barnard (J-PA) | March 4, 1827 |
| 35 | Daniel Webster (AJ-MA) | June 8, 1827 |
| 36 | Jacob Burnet (AJ-OH) | December 10, 1828 |
| 37 | James Iredell (J-NC) | December 15, 1828 |
| 38 | John Holmes (AJ-ME) | January 15, 1829 | Former representative |
| 39 | Charles Edward Dudley (J-NY) | January 15, 1829 |
| 40 | George Mortimer Bibb (J-KY) | March 4, 1829 | Former senator (3 years) |
| 41 | George Michael Troup (J-GA) | March 4, 1829 | Former senator (1 year, 10 months) |
| 42 | Thomas Buck Reed (J-MS) | March 4, 1829 | Former senator (1 year, 2 months) |
| 43 | John McLean (J-IL) | March 4, 1829 | Former senator (3 months) |
| 44 | Edward Livingston (J-LA) | March 4, 1829 | Former representative (12 years) |
| 45 | Peleg Sprague (AJ-ME) | March 4, 1829 | Former representative (4 years) |
| 46 | Theodore Frelinghuysen (AJ-NJ) | March 4, 1829 | New Jersey 13th in population (1820) |
| 47 | John Middleton Clayton (AJ-DE) | March 4, 1829 | Delaware 22nd in population (1820) |
| | Felix Grundy (J-TN) | October 19, 1829 |
| | John Forsyth (J-GA) | November 9, 1829 |
| | Bedford Brown (J-NC) | December 9, 1829 |
| | Robert Huntington Adams (J-MS) | January 6, 1830 |
| | Arnold Naudain (AJ-DE) | January 13, 1830 |
| | George Poindexter (J-MS) | October 15, 1830 |
| | David Jewett Baker (D-IL) | November 12, 1830 |
| | John McCracken Robinson (J-IL) | December 11, 1830 |