Places We Protect

Greybull River Basin

The Greybull River travels from peaks to sagebrush flats at its confluence with the Bighorn River.

Early morning view of the mountains near Pitchfork Ranch.
Greybull River Basin Early morning view of the mountains near Pitchfork Ranch. © 2001 Edward Orth

Native American tribes named the Greybull River after an albino bison bull that once roamed the area. The river runs through some of the most remote backcountry in the Greater Yellowstone. Along its 90-mile corridor, water travels from snow-capped peaks in the Absaroka Mountains to sagebrush flats at its confluence with the Bighorn River.

The Greybull River watershed is famed for supporting the best genetically-pure populations left of Yellowstone cutthroat trout, a species decimated elsewhere in the West by non-native species and altered water flows. The river’s high-quality aquatic habitat is spurring efforts among many landowners to join with partners to protect and restore this biologically-important watershed.

Northwest Wyoming, on the east flank of the Greater Yellowstone Ecosystem

More than 400,000 acres

The Greybull River Basin is classic Wyoming big sage country, interspersed with mixed-grass prairie, salt desert scrub and saltbush flats. At its higher elevations, lodgepole and limber pine, aspens and forested riparian areas dominate. Rare plants in this site include Evert’s waferparsnip, hairy prince’s plume and Rocky Mountain twinpod.

The Greybull River supports Yellowstone cutthroat trout, a species that has endured population extinction and fragmentation throughout much of its historic range. Aquatic habitats throughout the region also provide good nesting sites for amphibians such as the boreal toad, the Columbia spotted frog and the northern leopard frog. This area is a natural east-west migration route for moose, elk, mule deer and bighorn sheep moving from Yellowstone National Park, through the Absarokas, to their winter ranges in the Greybull River watershed. Black-footed ferrets were discovered here in 1981 after being presumed extinct.

Why the Conservancy Selected This Site
The Greybull River Basin is one of Wyoming’s highest-quality aquatic habitats. Water is life in the desert basins that surround the Greybull River—these freshwater ecosystems deliver nutrients to wetlands and are essential for wildlife. Invasive species are an increasing concern along the river’s corridor, choking out native plants and altering the integrity of the watershed. In addition, the basin stands to lose much of its quality status if existing large tracts of private land become fragmented with rural subdivisions.

What the Conservancy Has Done/Is Doing
The Conservancy is working in the Greybull River Basin with numerous landowners who want to see the watershed protected. Conservation easements offer a solution, preventing the fragmentation of private ranch lands. The historic Pitchfork Ranch has secured a conservation easement on over 13,000 acres of its private rangelands and river corridor, and the Conservancy recently sold property on nearby Sheep’s Point to conservation buyers who will protect important elk winter range with a donated easement to the Rocky Mountain Elk Foundation.

Help Protect the Greybull River

Support our work in Wyoming, including the preservation of our freshwater ecosystems in the Greybull River Basin, by making a charitable contribution today.