Oil refining in Wyoming began in 1895. By the 1920s the state boasted 16 refineries, with Standard Oil’s plant at Casper by far the largest. Production tracked oil booms and busts throughout the 20th century, culminating in the 1991 shutdown of Casper’s Amoco (formerly Standard) Refinery. Six refineries remain in production today.
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.
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.