Prospectors first struck oil in the Salt Creek Oil Field in northern Natrona County, Wyo. late in the 1880s. The first gusher came in in 1908. The subsequent boom lasted until the late 1920s, peaking in 1923, when the field produced more than 35 million barrels of oil. Tom Wall, who went to work in the field in 1917, stayed for decades and in the 1970s wrote out his memories of life in the oil patch through boom and bust. After 125 years and thanks to new technologies, the Salt Creek Field continues to produce today.

Wyoming’s first state prison was located in Rawlins, Wyo., and housed inmates for 80 years, beginning in 1901. In 1988, a joint powers board turned the abandoned building into a museum and renamed it the Wyoming Frontier Prison. Visitors today can tour the cells and see the grounds where 13,500 prisoners, including 11 women, served time.

Elwood Mead was only 30 in 1888 when Territorial Gov. Thomas Moonlight hired him to bring order to Wyoming’s water law. As territorial engineer Mead did just that, and his ideas were written into the state constitution adopted in 1890. Mead spent only 11 years in Wyoming, but all his life carried with him what he learned in the state.

Pinedale, Wyo. was founded in 1904, incorporated in 1912 and became seat of brand-new Sublette County in western Wyoming in 1921, when the town still boasted only about 100 people. Despite its isolation, the town survived well through the 20th century on ranching and tourism. It began to change more quickly in the early 1990s, as development sped up in the nearby Pinedale Anticline and Jonah natural gas fields. Today, with more than 2,000 people, the town works hard to keep its traditions while dealing with steady, industrial growth.

One of Wyoming’s early large-scale irrigation projects dates to the 1880s in what’s now Platte County, Wyoming and the county, organized in early 1913, still is perhaps best known for its reservoirs and recreation areas. The Oregon Trail ruts and Register Cliff near Guernsey serve as reminders of the pioneer heritage of the area and a coal-fired power plant near Wheatland provides jobs and economic stability.

After the Burlington Railroad reached Sheridan, Wyo. in 1892, coal camps—company towns for miners and their families—were established next to a series of mines north of the town. The mines served local and regional markets as well as the railroad. By 1910, a total of around 10,000 people lived in these camps—Dietz, Kooi, Monarch, Acme and Carneyville, later renamed Kleenburn—more than lived in Sheridan. A busy electric railway ran the 15 miles from town to the camps and back. Most of the miners were immigrants, more than half of them Polish, and their descendants still play vital roles in Sheridan County today.

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.

Point of Rocks Stage Station, 25 miles east of present Rock Springs, Wyo., was built in 1862 by the Overland Stage Company. The station was attacked and burned at least once by Indians, and stagecoach passengers were supposedly robbed and murdered nearby by the notorious outlaw and onetime stage-line superintendent Jack Slade. Point of Rocks Stage Station has been a school, freight station, store, ranch headquarters and a home. It is one of the only stage stations remaining intact on the Overland Trail. This site is on the National Register of Historic Places.

The Durlacher House in Laramie, Wyo. was built in 1878 for Civil War veteran Simon Durlacher. Durlacher arrived in town a decade earlier and just one month before the Union Pacific Railroad tracks reached Laramie. The house, designed by architect Charles Klingerman in late-Victorian Queen Anne style, was also used as a church and now is used by a private business. The Durlacher House is listed on the National Register of Historic Places.

Tracing its roots to a work camp for men digging irrigation ditches early in the 20th century, Powell, Wyoming, in northern Park County, remains an agricultural hub. Its economy has been boosted over the last century, however, by nearby coal mines and oil wells, and by public schools, a hospital and a community college, the last three of which are now the town’s largest employers. In 1994, Powell was one of 10 municipalities named an All-America City by the National Civic League.