Mastodon State Park is a little gem tucked away in Jefferson County, just south of Arnold. This park is the site of the Kimmswick Bone Bed, a famous deposit of Pleistocene ice age fossils. Why so famous? Because in 1979 archeologists studying here were finally able to prove that humans once roamed alongside—and hunted--giant ice age beasts, like the mastodon.
Mastodon State Park is an easy drive down Hwy 55, about 8 miles south of Arnold in Imperial.
The park has a certain Dr. Jekyll and Mr. Hyde quality to it. On the one hand, it’s an internationally famous archeological site, complete with a museum dedicated to the mastodon. On the other hand, it’s a beautiful park with three trails and a crystal clear creek to splash around in. The two aspects of the park are split by Seckman Road, meaning you could park at the museum and not even know about the main trailhead or see the playground and picnic site.
The museum is small, but worth the visit if you’re curious about mastodons. There’s a replica of a mastodon skeleton and a scene showing what ice age humans might have looked like. Don’t miss the film shown in the auditorium, it’s full of interesting facts about mastodons, the archeological digs that have been studying them since 1839 and the group of citizens who rallied together to save the fossils from certain destruction when Interstate 55 was built.
The trails are short, with two of them perfect for a causal stroll and a third that is more of a challenge.
The Wildflower Trail is the only trail accessed from the museum parking lot. It’s a short 0.4 mile loop that is not handicapped accessible and includes a long wooden staircase down to the Kimmswick Bone Bed. There’s nothing to see at the old dig site, because the tunnel leading to the underground archeological site was capped with concrete to keep it safe from thieves. The trail is wooded and you’ll see the remains of a limestone quarry that once operated here.
The Spring Branch Trail is 0.8 mile loop accessed from the picnic area in the southern side of the park. If you stopped at the museum, you will need to drive to the second parking area, off Seckman Road. This trail is flat with a surface of firm gravel, so is considered handicapped accessible. Wander down this trail to find a spring fed creek with a rock beach that kids will love to explore. You’ll have to climb a steep bank to get to the creek, so that part is not for wheelchairs (but a light stroller could be carried down).
The Limestone Hill Trail is the most challenging, but still a doable 1.75 miles long. Of course, about half of that distance is spent climbing up or down the rugged hillside. Most of the trail cuts through dense forest, but a short stretch crosses a grassy field. There are some very steep hills and a little tricky footing, so this trail is not for very small children.
If you go, remember a water bottle and bug spray for the trail, along with water shoes if you plan to visit the creek. You can picnic in the park and dogs are welcome on the trail (but not in the museum). The museum is close to the Imperial exit, so food options are plentiful. If you want to make a day of it, visit nearby Kimmswick for some .
Mastodon State Park
1050 Charles J. Becker Drive
Imperial, MO 63052-3524
Park Office: 636-464-2976
Addmission: the museum charges $4 per adult, kids under 15 are free.
Hours: 8 a.m. to 30 minutes past sunset for the park grounds. The museum is open from 9 a.m. to 4:30 p.m. Monday-Saturday and from noon to 4:30 p.m. Sunday. During the winter the museum is only open on weekends.