| 1812 |
1 October |
Cape Girardeau, New Madrid, St. Charles, St. Louis, and Ste. Genevieve |
| 1813 |
21 August |
Washington |
| 1816 |
23 January |
Howard |
| 1818 |
8 December |
Jefferson |
| 11 December |
Franklin, Wayne |
| 14 December |
Lincoln, Madison, Montgomery, Pike |
| 17 December |
Cooper |
| 1820 |
16 November |
Boone, Chariton, Cole, Lillard (now Lafayette), Perry, Ralls, Ray |
| 25 November |
Callaway, Gasconade, Saline |
| 1821 |
19 December |
St. Francois |
| 28 December |
Scott |
| 1822 |
2 January |
Clay |
| 1826 |
15 December |
Jackson |
| 23 December |
Marion |
| 1829 |
22 January |
Randolph |
| 23 January |
Crawford |
| 1831 |
6 January |
Monroe |
| 1833 |
2 January |
Carroll, Clinton, Greene, Lewis |
| 5 January |
Morgan, Ripley, Warren |
| 19 January |
Pulaski |
| 26 January |
Pettis |
| 1834 |
13 December |
Rives (later Henry), Johnson |
| 1835 |
2 January |
Shelby, Stoddard |
| 3 January |
Benton |
| 5 January |
Barry, Polk |
| 3 March |
Van Buren (later Cass) |
| 1836 |
16 December |
Clark |
| 17 December |
Audrain |
| 29 December |
Caldwell, Daviess |
| 1837 |
6 January |
Linn, Livingston, Macon, Taney |
| 6 February |
Miller |
| 1838 |
31 December |
Buchanan, Newton, Platte |
| 1841 |
29 January |
Adair, Andrew, Bates, Dade, Grundy, Jasper, Kinderhook (later Camden), Niangua (later Dallas), Nodaway (later Holt), Osage, Ozark (later Decatur, then Ozark again), St. Clair, Scotland, Shannon, Wright |
| 1845 |
14 February |
Atchison (defined as Allen in 1843), Cedar, Dunklin, Gentry, Harrison, Hickory, Knox, Lawrence, Mercer, Mississippi, Moniteau, Nodaway, Oregon, Schuyler, Sullivan (defined as Highland in 1843), Texas (defined as Ashley in 1843) |
| 25 February |
DeKalb, Reynolds |
| 28 February |
Putnam |
| 1846 |
18 December |
Dodge (abolished and added to Putnam in 1853) |
| 1849 |
24 February |
Laclede |
| 27 February |
Butler |
| 3 March |
McDonald (defined as Seneca in 1847) |
| 1851 |
10 February |
Dent, Stone |
| 19 February |
Pemiscot |
| 1 March |
Bollinger |
| 1855 |
27 February |
Vernon |
| 2 March |
Maries |
| 3 March |
Webster |
| 12 December |
Barton |
| 1857 |
17 February |
Iron |
| 2 March |
Howell |
| 29 October |
Douglas |
| 13 November |
Phelps |
| 1859 |
8 March |
Christian |
| 10 March |
Carter |
| 1861 |
8 February |
Worth |
| 1876 |
22 August |
St. Louis City separated from St. Louis County |