Is Mississippi and parts of Alabama, Tennessee, and Kentucky one giant island? 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?
Rhetorical questions:


Does the Erie Canal, which connects the Hudson River with Lake Erie make northern New York, southern Quebec, all of New England, all of New Brunswick, and the non-island parts of Nova Scotia an island?
Does the Chicago Sanitary and Ship Canal make all of the eastern part of the US an island?
Does Russia's Unified Deep Water System make Finland, Scandinavia, and Estonia an island, and mainland Europe another island?


Humankind has learned to connect waterways with canals, locks, and dams. The sudden appearance of those canals, locks, and dams does not suddenly make those now disconnected lands into islands. The connection between the Tombigbee and the Tennessee rivers involves manmade canyons, manmade canals, and several manmade locks and dams.

What about naturally narrow waterway connections? As an extreme example, consider the Committee's Punch Bowl in Alberta, Canada. This little lake has two little outlets. One of the outlets eventually joins the MacKenzie River, which flows into the Arctic Ocean. The other eventually joins the Columbia River, which flows into the Pacific Ocean.

This leads to one last rhetorical question: Does the natural existence of the Committee's Punch Bowl make most of Washington state, most of British Columbia, almost all of the Yukon, and all of mainland Alaska into a very large "island"? Most geographers would say no.