| Before: | 3rd Mississippi Legislature |
| After: | 5th Mississippi Legislature |
| Jurisdiction: | Mississippi |
| State: | Mississippi |
| Chamber1: | Mississippi State Senate |
| Chamber2: | Mississippi House of Representatives |
| Chamber2 Leader1 Type: | Speaker |
| Chamber2 Leader1: | Beverly R. Grayson |
| Chamber1 Leader2 Type: | President pro tempore |
| Chamber1 Leader2: | Thomas Torrence |
| Chamber1 Leader1 Type: | President |
| Chamber1 Leader1: | James Patton |
| Meeting Place: | Natchez, Mississippi |
| Body: | Mississippi Legislature |
The 4th Mississippi Legislature met from January 1, 1821, to February 12, 1821, in Natchez, Mississippi.[1]
The Mississippi State Senate was composed of the following. James Patton, the lieutenant governor of Mississippi, served ex officio as the president of the Senate. Thomas A. Willis was elected Secretary of the Senate, and J. Lowry was elected Door-Keeper. On January 15, 1821, Thomas Torrence was elected president pro tempore of the Senate.
| County District | Senator Name | |
| Adams | Joseph Sessions | |
| Charles B. Green | ||
| Amite | Thomas Torrence | |
| Wilkinson | John Joor | |
| Warren, Claiborne | William Willis | |
| Pike, Marion | David Dickson | |
| Jefferson, Franklin | Cowles Mead | |
| Lawrence, Covington, Wayne | Howell W. Runnels | |
| Jackson, Hancock, Green, Perry | Isaac R. Nicholson |
The Mississippi House of Representatives was composed of the following.[2] Beverly R. Grayson was elected Speaker of the House. Non-representatives Peter A. Vandorn and James R. Whitney were elected to the offices of clerk and door keeper, respectively.
| County | Representative |
| Adams | Samuel L. Winston |
| Beverly R. Grayson | |
| Samuel Montgomery | |
| Adams (Natchez) | James Foster |
| Amite | Richard Hurst |
| John Burton | |
| Wilie Jackson | |
| Claiborne | Henry G. Johnson |
| Thomas Freeland | |
| Covington | Garven Harris |
| Franklin | Bailey E. Chaney |
| Thomas Cotton | |
| Hancock | Noel Jourdan |
| Jackson | Thomas Bilbo |
| Jefferson | Isaac N. Selcer |
| William B. Blanton | |
| Lawrence | Thomas Anderson |
| Arthur Fox | |
| Marion | Francis B. Lenoir |
| Perry | R. H. Gilmer |
| Hugh McDonald | |
| Pike | William Dickson |
| James Robinson | |
| Vincent Gardner | |
| Warren | Francis Griffin |
| Wayne | Josiah Watts |
| Wilkinson | Gerard C. Brandon |
| William A. Richardson | |
| William Yerby |