# List of United States senators in the 20th Congress

This is a complete list of members of the United States Senate during the 20th United States Congress listed by seniority, from March 4, 1827, to March 3, 1829.
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 1828 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 1829 (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 1831 (AL, DE, GA, IL, KY, LA, MA, ME, MS, NH, NJ, RI, SC, TN, VA, and VT.) |
| Class 2 | Terms of service of senators that expired in 1833 (CT, DE, IN, MA, MD, ME, MO, MS, NC, NJ, NY, OH, PA, RI, 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 | Nathaniel Macon (J-NC) | December 5, 1815 |
| 3 | James Noble (AJ-IN) | December 11, 1816 |
| 4 | Mahlon Dickerson (J-NJ) | March 4, 1817 |
| 5 | Thomas Hill Williams (J-MS) | December 10, 1817 |
| 6 | Jesse Burgess Thomas (AJ-IL) | November 23, 1818 |
| 7 | Richard Mentor Johnson (J-KY) | December 10, 1819 |
| 8 | William Rufus de Vane King (J-AL) | December 14, 1819 |
| 9 | John Chandler (J-ME) | June 14, 1820 |
| 10 | Nehemiah Rice Knight (AJ-RI) | January 9, 1821 |
| 11 | Martin Van Buren (J-NY) | March 4, 1821 | New York 1st in population (1810) |
| 12 | Horatio Seymour (AJ-VT) | March 4, 1821 | Vermont 15th in population (1810) |
| 13 | David Barton (AJ-MO) | August 10, 1821 | Alphabetical (Ba) |
| 14 | Thomas Hart Benton (J-MO) | August 10, 1821 | Alphabetical (Be) |
| 15 | John Henry Eaton (J-TN) | September 27, 1821 |
| 16 | Samuel Smith (J-MD) | December 17, 1822 |
| 17 | John Branch (DR-NC) | March 4, 1823 | Former governor; North Carolina 4th in population (1820) |
| 18 | Samuel Bell (AJ-NH) | March 4, 1823 | Former governor; New Hampshire 15th in population (1820) |
| 19 | Robert Young Hayne (J-NH) | March 4, 1823 |
| 20 | Josiah Stoddard Johnston (AJ-LA) | January 15, 1824 |
| 21 | Charles Dominique Joseph Bouligny (AJ-LA) | November 19, 1824 |
| 22 | Thomas Willis Cobb (J-GA) | December 6, 1824 |
| 23 | Littleton Waller Tazewell (J-VA) | December 7, 1824 |
| 24 | Dudley Chase (AJ-VT) | March 4, 1825 | Former senator |
| 25 | William Hendricks (AJ-IN) | March 4, 1825 | Former representative (5 years) |
| 26 | William Henry Harrison (AJ-OH) | March 4, 1825 | Former representative (3 years) |
| 27 | John Rowan (J-KY) | March 4, 1825 | Former representative (2 years) |
| 28 | William Marks (AJ-PA) | March 4, 1825 | Pennsylvania 2nd in population (1820) |
| 29 | John Macpherson Berrien (J-GA) | March 4, 1825 | Georgia 11th in population (1820) |
| 30 | Elias Kent Kane (J-IL) | March 4, 1825 | Illinois 24th in population (1820) |
| 31 | Levi Woodbury (J-NH) | March 16, 1825 |
| 32 | Calvin Willey (J-CT) | May 4, 1825 |
| 33 | Hugh Lawson White (J-TN) | October 28, 1825 |
| 34 | Ashur Robbins (AJ-RI) | October 31, 1825 |
| 35 | Nathan Sanford (AJ-NY) | January 14, 1826 |
| 36 | Ezekiel Forman Chambers (AJ-VA) | January 24, 1826 |
| 37 | Nathaniel Silsbee (AJ-MA) | May 31, 1826 |
| 38 | Ephraim Bateman (AJ-NJ) | November 10, 1826 |
| 39 | John McKinley (J-AL) | November 27, 1826 |
| 40 | William Smith (DR-SC) | November 29, 1826 |
| 41 | Henry Moore Ridgely (J-DE) | January 12, 1827 |
| 42 | Powhatan Ellis (J-MS) | March 4, 1827 | Former senator |
| 43 | Louis McLane (J-DE) | March 4, 1827 | Former representative (10 years) |
| 44 | John Tyler (J-VA) | March 4, 1827 | Former representative (4 years, 2 months) |
| 45 | Samuel Augustus Foot (AJ-CT) | March 4, 1827 | Former representative (4 years, 0 months) |
| 46 | Albion Keith Parris (J-ME) | March 4, 1827 | Former representative (2 years) |
| 47 | Isaac Dutton Barnard (J-PA) | March 4, 1827 |
| 48 | Daniel Webster (AJ-MA) | June 8, 1827 |
| | Oliver Hillhouse Prince (J-GA) | November 7, 1828 |
| | Jacob Burnet (AJ-OH) | December 10, 1828 |
| | James Iredell Jr. (J-NC) | December 15, 1828 |
| | John Holmes (DR-ME) | January 15, 1829 | Former representative |
| | Charles Edward Dudley (J-NY) | January 15, 1829 |