Mastodon State Historic Site preserves one of the most significant Ice Age fossil beds in North America, tucked into the rolling hills of Jefferson County, Missouri. Spanning 425 acres along the banks of the Kimmswick bone bed, this site is where archaeologists first proved that humans and mastodons coexisted — a discovery that rewrote our understanding of early American history.

The centerpiece is the Kimmswick Bone Bed, where Clovis points were found alongside mastodon bones in the 1970s. The on-site museum houses full-scale mastodon replicas, fossil displays, and interactive exhibits that bring the Pleistocene era to life — making it a standout destination for families and history enthusiasts alike.

Beyond the museum, the park offers several miles of hiking trails that wind through limestone bluffs, wildflower meadows, and wooded bottomlands along Rock Creek. The Limestone Hill Trail climbs to scenic overlooks, while the shorter Groundsloth Trail is accessible for most skill levels. Picnic areas with shelters are available for day use.

Spring and fall deliver the best conditions for exploring the trails, with mild temperatures and vibrant foliage in October. Summer visits work well for the air-conditioned museum, though humidity can make the trails less comfortable. Winter hours may be limited, so check ahead.

Expect a quieter, more reflective experience here than at Missouri’s larger state parks. There are no camping facilities on-site, but nearby Mastodon and Jefferson County parks offer additional outdoor options within a short drive.

Explore Nearby

• Meeting of the Great Rivers Scenic Route — Scenic Byway in Illinois
• Mary’s River Covered Bridge — Covered Bridge in Illinois
• Gillespie Lake — Public Land in Alaska
• Mark Twain National Forest — National Forest in Missouri
• Shawnee National Forest — National Forest in Illinois