In 1843, explorer John C. Frémont reported coal in what’s now southwest Wyoming. In the 1860s, the route of the new transcontinental railroad across Wyoming was chosen partly to access abundant coal deposits for fuel for the locomotives. Coal mining boomed, labor strife increased and Wyoming’s coal industry thrived despite worker strikes and a number of horrific mine accidents. Today, the state produces 40 percent of the nation’s coal, most of it from huge strip mines in the Powder River Basin in northeast Wyoming, for rail shipment to electric power plants in 34 states.

Hanna, Wyo., best known for its coal mines, was founded in 1889 by the Union Pacific Coal Co. as a company town. It has survived mining disasters and a long cycle of booms and busts. The last mines around Hanna closed in the mid-2000s. The town survives today as a bedroom community, with hopes of future mineral development.

Oil seeps were reported often in the early 19th century in what later became Wyoming; it was sold, for example to Oregon Trail travelers for wagon lubricant. The first producing well in Wyoming Territory was drilled in 1883 at Dallas Dome southeast Lander. Perhaps the state’s best-known historic oil producing region is the Salt Creek Field, north of Casper, which was one of the world’s largest-producing fields in the 1920s. Oil remains an important part of Wyoming’s economy and culture today, and the state is ranked high among the top national producers.

The Powder River Basin sports a colorful history. Bones of bison slaughtered by people, found south of Sundance, Wyo., date back 6,000 years, and northeast Wyoming remained a favorite hunting ground for American Indians into the late 19th century. At that time the Powder River Basin was the scene of violent conflicts between the Indians and U.S. military men. Abundant grass made this region a favored spot for cattle and sheep ranchers. Under the grass is coal—so much of it that about 40 percent of the coal mined in the U.S., comes from the Powder River Basin.