Mastodon State Historic Site is off I-55 exit 186 at 1050 Charles J. Becker Dr. The Kimmswick Bone Bed, an area rich in Pleistocene fossils and bones, is preserved at the 425-acre site. Discovered in the early 19th century, this fossil bed yielded more than 60 mastodon skeletons, one of which is displayed at the site's museum. The museum recounts the history of the bone bed and the ancient Clovis culture through a movie and relics found on the site. Several trails cross the park.
Hours: Grounds open daily 8 a.m.-30 minutes after dusk. Museum open Mon.-Sat. 9-4:30, Sun. noon-4:30, Mar. 16-Nov. 14; Fri.-Sat. and Mon. 11-4, Sun. noon-4, rest of year. Closed Jan. 1, Easter, Thanksgiving and Christmas.