

| COUNTY | CREATED | FROM COUNTY | SEAT |
| ADAMS | 1799 | The Natchez District | |
| ALCORN | 1870 | Tippah, Tishomingo | Corinth |
| AMITE | 1809 | Wilkinson | Liberty |
| ATTALA | 1833 | Choctaw Cessions | Koscuiko |
| BENTON | 1870 | Marshall, Tippah | Ashland |
| BOLIVAR | 1836 | Choctaw Cessions | Cleveland |
| CALHOUN | 1852 | Lafayette, Yalobusha | Pittsboro |
| CARROLL | 1833 | Choctaw Cessions | Carrolton |
| CHICKASAW | 1836 | Chickasaw Cessions | Houston |
| CHOCTAW | 1833 | Chickasaw Cessions | Ackerman |
| CLAIBORNE | 1802 | Jefferson | Port Gibson |
| CLARKE | 1833 | Washington | Quitman |
| CLAY | 1871 | Chickasaw, Lowndes, Monroe, Oktibbeha | West Point |
| COAHOMA | 1836 | Chickasaw Cession | Clarksdale |
| COPIAH | 1823 | Hinds | Hazelhurst |
| COVINGTON | 1819 | Wayne, Lawrence | Collins |
| DeSOTO | 1836 | Indian Cessions | Hernando |
| FORREST | 1906 | Perry | Hattiesburg |
| FRANKLIN | 1809 | Adams | Meadsville |
| GEORGE | 1910 | Greene, Jackson | Lucedale |
| GREENE | 1811 | Amite, Franklin, Wayne | Leaksville |
| GRENADA | 1870 | Carroll, Montgomery, Warren, Webster, and Yalobusha | Grenada |
| HANCOCK | 1812 | Mobile District | Bay St. Louis |
| HARRISON | 1841 | Hancock, Jackson | Gulfport |
| HINDS | 1821 | Choctaw Cessions | Jackson |
| HOLMES | 1833 | Yazoo | Lexington |
| HUMPHREYS | 1918 | Holmes, Sunflower, Washington, Yazoo | Belzoni |
| ISSAQUENA | 1844 | Washington | Mayersville |
| ITAWAMBA | 1836 | Chickasaw Cessions | Fulton |
| JACKSON | 1812 | Mobile District | Pascagoula |
| JASPER | 1833 | Indians Lands | Bay Springs |
| JEFFERSON | 1799 | Natchez | Fayette |
| JEFFERSON DAVIS | 1906 | Covington, Lawrence | Prentiss |
| JONES | 1826 | Covington, Wayne | Ellisville |
| KEMPER | 1833 | Choctaw Cessions | DeKalb |
| LAFAYETTE | 1836 | Chickasaw Cessions | Oxford |
| LAMAR | 1904 | Marion, Pearl River | Purvis |
| LAUDERDALE | 1833 | Choctaw Cessions | Meridian |
| LAWRENCE | 1814 | Marion | Monticello |
| LEAKE | 1833 | Choctaw Cessions | Carthage |
| LEE | 1866 | Itawamba, Pontotoc | Tupelo |
| LEFLORE | 1871 | Carroll, Sunflower, Tallahatchie | Greenwood |
| LINCOLN | 1870 | Amite. Copiah, Franklin, LawrencePike | Brookhaven |
| LOWNDES | 1830 | Monroe | Columbus |
| MADISON | 1828 | Yazoo | Canton |
| MARION | 1811 | Amite, Franklin, Wayne | Columbia |
| MARSHALL | 1836 | Chickasaw Cessions | Holly Springs |
| MONROE | 1821 | Chickasaw Cessions | Aberdeen |
| MONTGOMERY | 1871 | Carroll, Choctaw | Winona |
| NESHOBA | 1833 | Choctaw Cessions | Philadelphia |
| NEWTON | 1836 | Neshoba | Decatur |
| NOXUBEE | 1833 | Choctaw Cessions | Macon |
| OKTIBBEHA | 1833 | Choctaw Cessions | Starksville |
| PANOLA | 1836 | Chickasaw Cessions | Batesville |
| PEARL RIVER | 1890 | Hancock, Marion | Poplarville |
| PERRY | 1820 | Greene | New Augusta |
| PIKE | 1815 | Marion | Magnolia |
| PONTOTOC | 1836 | Chickasaw Cessions | Pontotoc |
| PRENTISS | 1870 | Tishomingo | Booneville |
| QUITMAN | 1877 | Coahoma, Panola | Marks |
| RANKIN | 1828 | Hinds | Brandon |
| SCOTT | 1833 | Choctaw Cessions | Forest |
| SHARKEY | 1876 | Issaquena, Warren, Washington | Rolling Fork |
| SIMPSON | 1824 | Choctaw Cessions | Mendenhall |
| SMITH | 1833 | Choctaw Cessions | Raleigh |
| STONE | 1916 | Harrison | Wiggins |
| SUNFLOWER | 1844 | Bolivar | Indianola |
| TALLAHATCHIE | 1833 | Choctaw Cessions | Charleston |
| TATE | 1873 | DeSoto, Marshall, Tunica | Senatobia |
| TIPPAH | 1836 | Chickasaw Cessions | Ripley |
| TISHOMINGO | 1836 | Chickasaw Cessions | Luka |
| TUNICA | 1836 | Chickasaw Cessions | Tunica |
| UNION | 1870 | Pontotoc, Tippah | New Albany |
| WALTHALL | 1910 | Marion, Pike | Tylertown |
| WARREN | 1809 | Natchez District | Vicksburg |
| WASHINGTON | 1827 | Warren, Yazoo | Greenville |
| WAYNE | 1809 | Washington | Waynesboro |
| WEBSTER | 1874 | Chickasaw, Choctaw, Montgomery, Oktibbeha | Walthall |
| WILKINSON | 1802 | Adams | Woodsdville |
| WINSTON | 1833 | Choctaw Cessions | Louisville |
| YALOBUSHA | 1833 | Choctaw Cessions | Coffeyville |
| YAZOO | 1823 | Hinds | Yazoo City |