The smallest North American turtle lives in similar habitats to those of the Spotted Turtle (one of my favorite reptiles), and is a relative of the wonderful Wood Turtle. Nowadays, they have changed the official name to Bog Turtle.
(When I was young, I located a colony of Spotted Turtles in a sedgy marsh on the edge of a stream. On a sunny day, they'd be basking on the little tussocks, and splash into the shallow water when you walked by -not walked, actually - hopped from tussock to tussock in one's Keds. Spotted Turtles are listed as endangered too, now. Like Muhlenberg's, Spotteds seem to live in small colonies in specialized habitats which are senstive to human - and dog - intrusions.)
The Bog Turtle likes marshes with wet sedgy meadows in limestone areas. Despite their name, they do not live in acidic Sphagnum Bogs. They are rarely seen because they like to burrow in muck, but they are probably endangered. I have never seen one in the wild, even though our beaver marsh overflow is probably perfect habitat for them with its grassy hummocks, rivulets, beaver channels, damp meadows - and all of our Berkshire limestone and marble ledges and bedrock.
If you have ever encountered one, tell us.
The range of these turtles is dispersed:
Muhlenberg's Turtle was named after amateur botanist and sedge expert Gotthilf Henry Ernst Muhlenberg - an interesting character who played a role in the Revolution. Muhlenberg College in PA was named after his dad.