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A dark brown, football-shaped fossil fish with a fan-shaped tail and spines standing up on its back.
Destinations › North America › United States › Wyoming

Fossil Butte National Monument

Since: 1970 Open: 8 AM to 4:30 PM daily Price: Free
campaign Information: Temporary Phone Number for Visitor Center expand_more

Temporary Phone Number for Visitor Center — Our main phone number for the visitor center is temporarily disconnected. Please call 307-877-4456 to reach a ranger.

park Source: US National Park Service, refreshed several times a day.

Introduction

Fossil Butte National Monument is a significant paleontological site in Wyoming, showcasing fossils from the ancient Green River Formation. Visitors come to explore the well-preserved remains of fish, alligators, and other species that thrived in a subtropical ecosystem 50 million years ago.

The monument offers hiking trails and opportunities to witness fossil excavation during the summer months. The diverse weather conditions throughout the year can affect your visit, so be prepared for varying temperatures and potential snow in the colder seasons.

In pictures

Hills with tan and red sediments partially covered with green vegetation.
Hills with tan and red sediments partially covered with green vegetation.

Things to know

Expect cold temperatures in spring, fall, and winter.
Summer daytime temperatures can reach up to 90 °F (32 °C).
The Historic Quarry Trail is 2½ miles long, while the Nature Trail is 1½ miles.
Fossil excavation occurs on Fridays and Saturdays from 11 AM to 4 PM in summer.

Good to know

Accessibility: some trails are wheelchair accessible
Opening hours: 8 AM to 4:30 PM daily
Price: Free

Photo: NPS Photo