Casper’s Odd Fellows Building, constructed in 1952, reflects the modern-style architecture that was popular during the postwar era and serves as a reminder of the community development, planning and the social history of the time. This structure is named on the National Register of Historic Places.

Notorious outlaw Butch Cassidy and his Wild Bunch frequently crossed and hid out in Wyoming when on the run from the law. Cassidy’s 18-month incarceration at the Wyoming State Prison in Laramie, 1894-1896, is a definite fact. Other than that, stories place him and his gang all over the map, from Sundance to Brown’s Hole, and Powder Wash near Baggs to Hole in the Wall near Kaycee. Stories persist as well that Cassidy returned to Wyoming decades after his reported death in Bolivia in 1908, but no hard evidence has yet turned up.

From 1942 through most of 1945, about 10,000 Japanese-Americans from the West Coast of United States lived behind barbed wire in tarpaper barracks at the Heart Mountain Relocation Center between Cody and Powell, Wyo. in Park County—one of ten such camps around the nation during World War II. The center was briefly Wyoming’s third-largest town. When hundreds of young men in the camp were drafted into the U.S. military, 63 resisted, feeling they had been denied their constitutional rights. They and seven more leaders of the group were sentenced to federal prison. In the 1980s, Congress passed a law granting an apology and $20,000 to every survivor of the camps.

Though the site was an important river crossing on the early frontier, the town of Casper did not begin until 1888, when the Fremont, Elkhorn & Missouri Valley Railroad reached the area. The town immediately became an important shipping point for cattle and wool. The first oil refinery was built in 1895 to process crude oil from the Salt Creek Oil Field, 40 miles to the north. The first true oil boom began after 1910 and lasted through the mid 1920s, and the town’s fortunes have been closely connected to the energy business ever since. In 2010 the city’s population passed 55,000. Casper continues as a retail, medical and energy-industry service hub.

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.

Construction of Buffalo Bill Dam, completed in 1910 six miles west of Cody, Wyoming, was the key that opened about 90,000 acres in northwestern Wyoming to irrigated farming. Its construction was slowed by engineering difficulties and labor strife, but when it was finished stood as an engineering marvel, one of the first concrete arch dams built in the United States and the tallest dam in the world at the time.

Mary Hughes was just 17 years old in 1908 when the No. 1 Mine exploded twice in one day—and for the second time in five years—in Hanna, Wyo. Her story shows the devastating impact that coal mine accidents had on families like the Hugheses across Wyoming’s mining communities, and reveals her determination to survive disaster.

The Casper Army Air Base was built quickly in 1942 to train bomber crews for World War II combat. The facility trained more than 16,000 men before the end of the war. Its population grew to a third of the size of Casper’s, bringing prosperity and a lively social life to the town. The base closed in 1945, when the war ended.

In Wyoming, dry farming—growing crops without irrigation--began to become popular in the early 1900s. Vernon T. Cooke, first state director of dry farming, was extremely influential in promoting the method. Today, the University of Wyoming’s experimental agricultural station continues to develop dry farming techniques. 

On April 2, 1909, seven cowmen attacked a sheep camp near Spring Creek in the southern Big Horn Basin. The raiders killed three men, kidnapped two others, killed sheep dogs and dozens of sheep and destroyed thousands of dollars of personal property. It was the deadliest sheep raid in Wyoming history. Unlike many previous incidents after which raiders went unpunished, however, prosecutors this time were successful and five raiders were jailed, marking the end of 15 years or more of violence between cattle- and sheepmen.