Mississippi is the 20th State Admitted to the Union

The Mississippi Territory was organized on April 7, 1798, from territory ceded by Georgia and South Carolina. It was later twice expanded to include disputed territory claimed by both the United States and Spain. From 1800 to about 1830, the United States purchased some lands (generally through unequal treaties) from Native American tribes for new settlements of Americans. On December 10, 1817, Mississippi was the 20th state admitted to the Union.

http://en.wikipedia.org/wiki/Mississippi