Yep. You can't really swim around in any fresh water source down here without worrying about them. The Cape Fear River here has a bunch of big boys, on top of the occasional Bull Shark. We have the Battleship North Carolina as a floating museum and right across are two 15ft gators that nest.
I used to have dreams when I was little about there being alligators in the pond behind my grandmother's house. I guess you could call them nightmares, but I never really got close to them even in the dreams, and they never tried to come after me.
Bull Sharks = bad news.