He represents the American state. His human name is Jackson Jones, named after the state's capital city.
Mississippi is an elderly African-American man with black hair in a bowl-cut and brown eyes. He's often wearing a floppy, fisherman's hat, a button-down white shirt, baggy black jeans, a tan jacket, and carrying a fishing rod. He sometimes wears flip-flops, too.
Mississippi was originally a slave to various Southern states (including South Carolina at one point), but he remained cheery. He was once brow-beat into joining the Confederates, but was willing to fight for them. In modern days, he's a friendly and charming man who tends to be the wise man of the South. Due to building his apartment near the river, his place tends to get flooded a lot. He mostly makes his living as a fisherman. He's also a pretty good musician.
The two are good friends as they were on the same side during the Civil War. Alabama treated Mississippi like a brother and the two developed a close bond. The two also worked together during the Civil Rights Movement.
In the Civil War, Georgia often treated Mississippi in a rather cruel way. However, in modern day, the two seem to have reconciled. Georgia often comes to Mississippi for advice and often says "Ol' Miss always knows what to say!"
The two are close friends and war buddies from the Civil War. Louisiana often saves Mississippi when his apartment floods. The two often hang out.