In 1857, the U.S. Congress passed the Pacific Wagon Road Act, allowing the survey and construction of wagon roads. A segment of the first such national road built in the West is the Lander Trail, a section 229 miles in length between a point near present-day South Pass, Wyo., and Fort Hall, Idaho. The route saved travelers 60 miles compared to the more traditional route of the Oregon-California Trail through Fort Bridger. The Lander Trail was named for Frederick William Lander, chief engineer and later superintendent for the project—a volatile but effective leader who was nationally famous in his day.

In January 1958, teenagers Charles Starkweather and Caril Ann Fugate went on a 10-victim killing spree that began in Nebraska and ended near Douglas, Wyo., after a high-speed chase through the middle of town. Starkweather was later executed in Nebraska, and Fugate was paroled after 18 years.

Natural gas has been flowing from the Jonah Field and Pinedale Anticline in western Wyoming since the early 1990s, bringing with it substantial profits, tax revenues, prosperity, social change, air pollution, and declines in local mule-deer populations. The story goes to the heart of Wyoming’s oil and gas culture, and raises important questions about energy production’s long-term costs and benefits.

In April 1892, a private army of 52 cattle barons, their employees and hired Texas guns invaded Johnson County in northern Wyoming, intending to kill as many as 70 men they suspected of being rustlers or rustler sympathizers. The invaders managed to kill two men before word got out, and they were surrounded by an angry posse. Troops from nearby Fort McKinney intervened. The invaders were escorted back to Cheyenne, where they were charged but never brought to trial. The event ended in ambiguity and political division in the new state of Wyoming.

Western Wyoming’s Green River drains 4,000 miles of forested mountains and high desert, home to migrating wildlife, grazing cattle, a few thousand people, and in recent decades a booming natural-gas business. Since prehistoric times, people have worked to balance the basin’s resources for their own benefit — and that struggle continues today.

Lucy Morrison Moore, “The Sheep Queen of Wyoming,” was a leading sheep producer during the heyday of public-land sheep ranching from the 1880s to 1920s. Smart, tough and slightly eccentric, she and her family survived brutal, isolated conditions and attacks from cattle ranchers.

Mary Godat Bellamy, Wyoming’s first woman legislator, was elected to the state House of Representatives in 1910, where she sponsored bills aimed at improving the lives of women and children. She was active as well in the national movement for votes for women.

The Mineral Leasing Act of 1920 established the modern system by which oil and coal companies may lease federal land. This system has proven enormously beneficial to Wyoming’s state coffers since it was first enacted nearly 100 years ago. How this all came about is a story of early oil producers looking for a way around a presidential order and a highly contentious Supreme Court case, all with lucrative results for the state of Wyoming—and a stabilizing result for the industry.

Legend Rock, about 30 miles northwest of Thermopolis, Wyo., features nearly 300 images carved or pecked into a rock cliff by ancient peoples over thousands of years.

Accidents and disasters have plagued Wyoming coal mines since territorial times. In 1886, legislators created the office of the state mine inspector to help improve safety. Still, explosions and cave-ins killed hundreds of miners in the following decades. The worst accidents happened in Hanna in 1903 and near Kemmerer in 1923. Lawmakers continued to increase safety measures and eventually expanded the duties of the state mine inspector. Modern strip mining is far safer.