Apologies if this is a poorly written question, I'm writing this on my phone.
I noticed that there were a lot of rather long rivers in the region in question, and I began to wonder just how connected they are. I came up with the following path:
Start in Mobile, Alabama, and head north along the Tombigbee River past the Mississippi-Alabama border and into Mississippi. It seems to go through some name changes, but near the Tennessee-Alabama-Mississippi border, it connects with the Tennessee River. Follow the Tennessee River north through Kentucky and Kentucky Lake, where it will eventually meet the Ohio River. That, in turn, feeds into the Mississippi River, which flows back to the Gulf of Mexico.
It seems to me that it makes the region enclosed an island, since it is impossible to reach it without crossing a body of water. But is this significant in any other way? I can tell that not all the rivers flow in the same direction, and it's possible that some portions of the water around it were artificially created, is there anything else that comes as a result of this?