The old Mississippi capitol building, located just a few blocks from the current capitol, served as the seat of government from 1839 to 1903. A classic Greek Revival structure, it was the site of some of the state's most significant legislative acts, including its secession from the Union in 1861. Now restored as a museum, it features interactive exhibits detailing the history of the state that unfolded here.
If you go:
Open Tuesday through Saturday 9 to 5 and Sunday 1 to 5. Closed Mondays. Admission is free, but please call ahead for groups of 10 or more.
Links:

100 State Street
Jackson, Mississippi 39201 USA
lmiller@mdah.state.ms.us
Phone Numbers:
Museum Hostess
+1 (601) 576-6920
+1 (601) 576-6920
Museum Coordinator
+1 (601) 576-6902
+1 (601) 576-6902
Museum Director
+1 (601) 576-6934
+1 (601) 576-6934