Admitted to the Union on December 10, 1817 as the 20th state. Mississippi Territory was created in 1798.

• 1800 – 1810 federal censuses lost.
• 1820 federal census extant for all counties.
• 1830 federal census extant for all counties except Pike.
• 1840 – 1850 federal censuses extant for all counties.
• 1860 federal census extant for all counties except Hancock, Sunflower, and Washington.
• 1870 – 1940 federal censuses extant for all counties except for 1890.