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Places We Protect

Thunder Basin

Collaboration brings hope to eastern Wyoming’s rugged and remote grasslands.

Watch a video about Wyoming's grasslands

Learn how these people have come together with scientists, land managers and conservationists to help safeguard their unique homeland and the wildlife it supports.


Wyoming’s Thunder Basin tests our tolerance for wide-open spaces. People who don’t live here struggle to comprehend the apparent endlessness of a horizon rolling away into a vast, swallowing sea of open sky.

The Thunder Basin’s high, relatively cold climate has made its rich soil unattractive to the furrowing plows that overturned much of America’s Great Plains. As a result, these grasslands contain some of the most intact native prairie left in the U.S.

With time, impacts on Thunder Basin’s grasslands will continue to mount. Much has already changed since the first European explorers waded through the prairie—Bison that once dominated this landscape are long gone, and many grassland species face an uncertain future.

West of the Black Hills, encompassing the Cheyenne and Belle Fourche rivers

More than two million acres

The Thunder Basin grasslands are mixed-grass prairies, where fifty or more plant species may thrive in a two-acre area. These grasses are drought-tolerant and many are well-adapted to large grazing mammals. Lightning-sparked wildfires are what help many grass species germinate and reproduce. In some areas, grasslands give way to sagebrush, cactus, or woodlands with ponderosa pine, limber pine, or juniper.

Life recycled in grassland soils provides nutrients to a wide diversity of animals. Ferrugineous hawks, swift foxes, pronghorn and black-tailed prairie dogs all inhabit the Thunder Basin. The black-tailed prairie dog is particularly important for its role building burrows and cropping vegetation that creates habitats for other species. Many grassland birds migrate from as far away as Mexico and South America to spend part of each year in the Thunder Basin, including the burrowing owl, mountain plover and Sprague’s pipit.

Why the Conservancy Selected this Site
Grasslands are the least protected habitat on Earth. Fragmentation caused by residential development, invasion by non-native plants, coal and coal-bed methane mining, and altered natural fire patterns have all taken a toll. Fortunately, the Thunder Basin still contains a vast expanse of intact native prairie—due in part to the stewardship of landowners. As a result, the Conservancy and its partners have a chance to protect these grasslands now, while they still exist across their historic range.

What the Conservancy Has Done/Is Doing
In the Thunder Basin grasslands, federal and state lands intermingle with vast expanses of private lands ownership, even one of the largest coal companies in the U.S. Cooperative efforts that bring farmers, ranchers, and other landowners to the table are the only way we can help continue a tradition of conserving Wyoming’s native grasslands. By combining our efforts with coalitions such as the Thunder Basin Prairie Ecosystem Association, the Conservancy is exploring solutions that address human needs as well as conservation priorities.

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