I saw one swimming in the Pamlico Sound on the backside of Ocracoke last year.
I just remembered another cottonmouth story. Back in 1989 we were on vacation up in Maggie Valley. There was a zoo there that had a large collection of snakes, and they also had a snake pit where one of the employees would give presentations on the different kinds of snakes. The most aggressive snake in that entire pit was a baby cottonmouth. None of the others bothered him, but that little thing struck his boot again and again where you could see the teethmarks and venom spots. It makes my skin crawl just thinking about it.