The Powder River Basin: A Natural History

“This story of Powder River is—in reality—the story of grass,” Struthers Burt wrote in his lyrical 1938 book Powder River: Let ‘er Buck. “The search for it. The fight for it. The slow disappearance of it.”

The term "Powder River Basin" is often used loosely to to refer to the drainages of the Tongue, Powder and other streams in northeast Wyoming. Wyoming Water Development Commission.Grass has translated to the economic basis for cultures in western North America for 10,000 years or more. Meat, leather and wool came first from free-roaming bison and other game and recently from domesticated cattle and sheep. Tens of millions of plains bison once roamed between Alberta and Florida.

But Burt didn’t consider another form of vegetation that has since become an even bigger piece of the Powder River Basin story: plants buried millions of years that have cured into thick coal seams underground. Today northeast Wyoming produces 40 percent of the nation’s coal, which is burned to generate about a fifth of the country’s electricity. The region is home to the eight largest U.S. coalmines. About 13.9 percent of U.S. greenhouse gas emissions come from burning Powder River Basin coal.

This industry also powers a substantial portion of Wyoming’s economy. In 2008, the mines directly employed more than 6,800 workers. In 2010, Campbell County, where most of the Powder River Basin coal mines are located, produced nearly $4.5 billion worth of taxable minerals, more than any other Wyoming county.

Generally the Powder River Basin refers to the lower elevation lands reaching from the Bighorn Mountains in north central Wyoming to the Black Hills on the Wyoming/South Dakota border, even though this region also includes the watersheds of the Tongue, Little Missouri, Belle Fourche and Cheyenne rivers, tributaries of the Yellowstone and Missouri.

People, meanwhile, have lived in the Powder River Basin for thousands of years. Archaeologists unearthed huge bison bones from an arroyo trap on the Hawken Ranch south of Sundance, Wyo., in the 1970s and dated them to more than 6,000 years ago. Several other similar sites are scattered across the northeast corner of Wyoming. Before horses, hunters relied on geography and even elaborate wood corrals to trap and slaughter their prey. One such site, the Vore Buffalo Jump east of Sundance holds bones from an estimated tens of thousands of bison that died there over the span of hundreds of years.

The Irigary Bridge over Powder River near Sussex, Wyo. about 20 miles downstream from Kaycee. Library of Congress photo.