This is a rattler of the central US, ranging from Ontario to Mexico and generally preferring grasslands and marshes. I have never seen one, but I have never searched for snakes in the central US. However, I once came across a DeKay's Snake in central Ohio on a hike. Took a photo. The field biologist said they had never been recorded in central Ohio so I guess I made history in a small way.
Have you ever seen a Massasauga? This guy is well-camouflaged in the grasses. It is good not to be a mouse.