Fossil Butte National Monument

Located in beautiful southwest Wyoming, Fossil Butte National Monument is one of the largest deposits of freshwater fish fossils in the world. In prehistoric times, this part of Wyoming was a sub-tropical lake ecosystem. The area’s calm water, lack of scavengers and fine sediment all worked together to create the perfect conditions for preserving fossils.

Today, Fossil Butte National Monument protects Fossil Lake and portions of the Green River Lake ecosystem. This area is rich with fossils of fish, alligators, bats, turtles, small horses, insects, and many other species of plants and animals.

At the base of Fossil Butte are the bright red, purple, yellow and gray beds of the Wasatch Formation. Eroded portions of these horizontal beds slope gradually upward from the valley floor and steepen abruptly. Overlying them and extending to the top of the butte are the much steeper buff-to-white beds of the Green River Formation, which are about 300 feet thick.

Fossil Butte Quarry Program

Fossil Butte quarry programs take place Fridays and Saturdays mid-June through late August between 11 a.m. and 3 p.m. Program participants meet at the Nature Trail and hike a half mile to the quarry, where they learn about ongoing research at the site and help rangers search for fossils. All fossils found during the program are collected by Fossil Butte and contributed to the site’s scientific research. Anyone planning to attend a quarry program should wear hiking shoes, pack water and sun protection, and expect the program to last for about an hour and a half. 

Fossil Butte Hiking

Fossil Butte offers several maintained trails and additional hiking along two-track dirt roads that spur off the Scenic Drive. All hikes are less than three miles and allow visitors to take in the site’s unique landscape and geological features. Summer hikers should plan to pack sun protection, water and bug spray. Check trail and road conditions before hiking at Fossil Butte National Monument in the winter.

Fossil Butte Visitor Center

Fossil Butte’s visitor center acts as a museum for this ancient site, featuring a number of exhibits that display over 300 fossils. Video programs, a fossil preparation lab and a fossil rubbing table all create a unique ways to discover this history of this site. With entire walls dedicated to displaying fossilized mammals, plants, birds, insects and more, the visitor center should be part of any Fossil Butte experience.

In addition to the fossils and rich history of the butte, visitors can take a ride along the site’s Scenic Drive, stop for lunch at a designated picnic area or attend a ranger program.