Also: The Alabama Gulf Coast. There's a "Beware of snakes and alligators sign" at a lagoon a few blocks from where I live on Mobile Bay, and with reason: Alligators do come up on land from time to time.

I'd expand your advice to say: "any freshwater body or estuary [salt + freshwater mix].” Alligators can (and do) swim in bodies of water that combine salt and freshwater.