The basin of the North Platte River takes up the southeastern quarter of Wyoming, plus a finger of land along the tributary Sweetwater River in the center of the state. The courses of the North Platte and Sweetwater determined early fur-trade and emigrant routes. Since that time, the basin’s water and other resources have continued to draw industry, stock raising, dams and irrigation—and people.

The story of uranium in Wyoming is a high-stakes drama whose cast includes fever-driven prospectors, ranchers defending their property rights, government officials intent on national security, entrepreneurs, engineers and world-class mining companies.

On Aug. 2, 1867, a large force of Oglala Sioux attacked woodcutters near Fort Phil Kearny. Soldiers assigned to protect the woodcutters took cover behind a ring of wagon boxes. After the intense battle, both sides claimed victory, and estimates of the dead and wounded varied widely.

The Vore Buffalo Jump, a natural sinkhole where ancient tribes drove bison to butcher them, now lies adjacent to I-90 near Sundance, Wyo., and is open to the public during the summer.

Wyoming’s sheep business never had the fame or cachet of Wyoming’s cattle business, but at the turn of the last century sheep raising was more widespread and probably more lucrative. Cattlemen, however, reacted violently to sheepmen’s entry onto the public range, and for a time deadly raids by cattlemen on flocks, sheepdogs and sheepherders were chronic. A gradual decline in wool and lamb prices since the 1920s has left only about a twentieth as many sheep on Wyoming ranges now as there were in 1909.

The Welsh-born Episcopal priest John Roberts arrived in 1883 at Fort Washakie on what’s now the Wind River Indian Reservation in Wyoming, became a friend of the Shoshone chief Washakie, and served the Shoshone and Arapaho people with a loving paternalism well into his old age. John Roberts died in 1949.

As many as half a million people crossed what’s now Wyoming in the mid-19th century before the transcontinental railroad was built. Their trails followed the North Platte and Sweetwater rivers west to South Pass, after which they divided into various routes bound for Oregon, Utah or California. They were making the journey of a lifetime, on routes blazed by Indians and trappers, and then worn deep and wide by thousands of wagons and perhaps millions of draft animals. These trails remain largely unchanged in Wyoming. Their white-topped wagons still hold an important place in the national imagination.

After World War II, the University of Wyoming was bursting with returning veterans just as the nation, nervous about Communist expansion worldwide, was sliding into the Cold War. UW trustees called for the investigation of textbooks in use on campus to determine if they were “subversive or un-American.” The faculty overwhelmingly resisted the move, and both sides reached a compromise guaranteeing academic freedom in the future.

The White Mountain Petroglyphs in the Red Desert north of Rock Springs, Wyo., feature hundreds of images carved into a rock face between 1,000 and 200 years ago. The site is on Bureau of Land Management land, and is open to the public.

Uinta County, one of the five counties of Wyoming Territory, was reduced to its present size in 1911. The Oregon, California, Mormon and Overland trails all passed through the county as well as the Union Pacific Railroad, the Lincoln Highway and Interstate 80. While the county is rich in natural resources like coal and oil and endures economic booms and busts as a result, agriculture continues to be a mainstay. Rancher John Myers established the first ranch on the Bear River drainage in 1858 and filed the first water right in what later became Wyoming Territory.