THE LAND BENEATH OUR FEET

Geology of
Beaverhead County

Ancient rocks, remarkable landscapes, and millions of years of geological history.

A REMARKABLE GEOLOGICAL LANDSCAPE

Written in Stone

Beaverhead County lies in one of Montana's most geologically fascinating regions. Its mountains and valleys preserve evidence of ancient seas, mountain-building events, volcanic activity, faulting, and erosion.

From quartz crystals in the Pioneer Mountains to evidence of an ancient meteorite impact, the region offers an extraordinary opportunity to explore Earth's history.

A GEOLOGICAL TREASURE

Crystal Park

Located in the Pioneer Mountains southwest of Wise River, Crystal Park is a popular public quartz crystal collecting area in the Beaverhead-Deerlodge National Forest.

Visitors can search for quartz crystals in designated collecting areas, making Crystal Park an unusual place where families and amateur rockhounds can experience geology firsthand.

The crystals occur in weathered geological material, and visitors may find clear, smoky, or other varieties of quartz.

Crystal Park is generally a seasonal destination because of its mountain location. Visitors should check current Forest Service information for road access, fees, collecting rules, and seasonal conditions before traveling.

U.S. Forest Service — Visitor Information ↗

Explore Crystal Park — Geology, Crystal Collecting & Visitor Information →

EXPLORE THE GEOLOGY

Geological Features and History

The county's varied terrain reveals a complex geological past, from ancient sedimentary rocks to younger volcanic deposits and mountain ranges shaped by tectonic forces.

AN ANCIENT IMPACT

Beaverhead Impact Structure

The Beaverhead impact structure is associated with evidence of a very large ancient meteorite impact. Shocked rocks and other geological clues have helped scientists investigate this remarkable event. Its original extent and geological history remain subjects of scientific study.

Explore the Beaverhead Impact Structure →

MOUNTAIN BUILDING

The Pioneer Mountains

The Pioneer Mountains contain a diverse collection of sedimentary, metamorphic, and igneous rocks. Their rugged terrain reflects a long history of mountain building, intrusion, faulting, and erosion.

Explore the Pioneer Mountains →

ROCKS AND FOSSILS

Ancient Seas and Fossils

Sedimentary rocks across southwest Montana record environments that existed long before today's mountains. Some formations preserve fossils and other evidence of ancient marine life.

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THE SHAPE OF THE LAND

Mountains, Faults and Valleys

Geological faulting and erosion helped create the region's distinctive mountain ranges and broad valleys. The Beaverhead, Big Hole, and surrounding landscapes tell different chapters of this story.

MINERAL RESOURCES

Minerals and Mining

Mineral deposits played a major role in the county's settlement and economy. Historic mining districts around Bannack and the Pioneer Mountains reflect the connection between geology and local history.

LEARN MORE

Geological Maps and Research

The Montana Bureau of Mines and Geology and the U.S. Geological Survey provide maps, publications, and research that help explain the area's geological history.

Montana Bureau of Mines and Geology ↗

Discover More of Beaverhead County's Geology

This section is being developed. Additional photographs, geological maps, notable formations, and educational resources will be added over time.

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