Eastern Massasauga Rattlesnakes live in an area that extends from western New York and southern Ontario to southern Iowa and a narrow band in northeastern Missouri. Historically, the snake's range covered this same area, but within this large area the number of populations and the number of snakes within populations have steadily shrunk.

The Eastern Massasauga Rattlesnake is generally found in small, isolated populations throughout its range. Today, the massasauga is listed as endangered, threatened, or a species of concern in every state and province in which it lives.

Adapted from the USFWS website, http://www.fws.gov/midwest/endangered/reptiles/eama/eama-fct-sht.html