In the United States, the western subspecies forms a wide intergrade area with the midland subspecies covering much of Illinois as well as a strip of Wisconsin along Lake Michigan and part of the Upper Peninsula of Michigan (UP). Further west, the rest of Illinois, Wisconsin and the UP are part of the range proper, as are all of Minnesota and Iowa, as well as all of Missouri except a narrow strip in the south. All of North Dakota is within range, all of South Dakota except a very small area in the west, and all of Nebraska. Almost all of Kansas is in range; the border of that state with Oklahoma is roughly the species range border, but the turtle is found in three counties of north central Oklahoma.
