Mississippi-in-Africa was a colony settled by freed
African-American slaves in present-day
Liberia. It existed from 1835 until 1842, when it was incorporated into the Commonwealth of Liberia. It is also the title of a nonfiction book about the recolonization effort (Alan Huffman, Gotham Books, 2004).
See also
Website for Alan Huffman's book Mississippi in Africa
http://www.mississippiinafrica.com/MSAfrica.htm