Kinkaid also has copperheads and cotton mouths.
I ran face to face with a medium sized cotton mouth at the spillway years ago, was going to net some minnows out of the pools there to go fishing but before I got started I saw a water snake in the pool.
I said to myself 'self that looks like a real cotton mouth'
Little snakey must have heard me because at that moment he opened his mouth and a pair of fangs dropped down.
Needless to say I left the minnows for him and called my dog away, and just fished with lures that day.

Had plenty of copperheads by the house south of murphysboro, but all the water snakes I saw there were non-venomous.

Never did have the pleasure of seeing a rattle snake there.

Never heard of massasaugas, only thought we had 3 types of venomous snakes in IL.