Natrona County’s Salt Creek Field is best known of Wyoming’s early oil fields, but five others—two in Park County and one each in Hot Springs, Niobrara and Converse counties—played important roles in the state’s 20th century transformation from an agricultural to an industrial economy.

A childhood love of adventure eventually led the Belgian Jesuit priest Father Pierre-Jean De Smet to become a missionary to the Indians of the Rocky Mountains. He traveled throughout the northern Rockies, along the way celebrating the first Catholic Mass in what’s now Wyoming on July 5, 1840, during the Green River Rendezvous. In 1851, members of his party named Lake De Smet for him as they traveled from the Missouri River in present Montana to assist in treaty negotiations with the plains tribes near Fort Laramie.

Fort Fetterman was established by the U.S. Army on the North Platte River near present Douglas, Wyo. in 1867. It served as a staging point for Gen. George Crook’s three campaigns against Cheyenne and Lakota Sioux Indians in 1876, near the end of the Indian Wars. The Army abandoned the post in 1882, and the settlement finally closed down a few years later when the railroad arrived at Douglas, seven miles to the south.

Delegates to Wyoming’s Constitutional Convention had to work quickly in 1889 to get a constitution adopted while Congress was still in session. Still, they managed to adopt some innovative ideas, especially in water law. The biggest stumbling block to statehood, in Congressional debate the following year turned out to be whether Wyoming had enough people. It was a close call.

The Greybull Hotel, built in 1916, was the first and largest of its kind in downtown Greybull, Wyo., to be constructed with brick and concrete. Its main commercial space has served as a bank, a clothing store and a bar; during Prohibition there was a speakeasy in the basement. The hotel’s location--at the corner of Greybull Avenue and Sixth Street and at the intersection of Wyoming Highway 14 and Wyoming Highway 16/20—was of primary importance in the early days and remains so today.

In 1869, Fort Fred Steele was built by the U.S. Army to protect workers on the advancing transcontinental railroad at the spot where the rails crossed the North Platte River. The fort was closed in 1886, and the site, containing foundations of the original buildings, was much later acquired by the state.

Tom Horn, stock detective and hired killer, was hanged in Cheyenne in 1903 for a crime he probably did not commit. He remains controversial because of lingering questions about his guilt and the nature of the trial. Horn’s death remains important as it shows the power of Wyoming’s cattle barons, once substantial, beginning at last to wane.

Fort Laramie began as a fur-trade post in 1834 near the confluence of the Laramie and North Platte rivers. Soon it changed into a post for the trade in buffalo robes, and for supplying emigrants bound west on the Oregon/California/Mormon Trail. In 1849 the post was purchased by the U.S. Army, and became an important supply, logistics and communications center for the Indian Wars campaigns of the next four decades. In recent decades the post has been carefully restored, and today is a National Historic Site.

Cantonment Reno, at the Powder River Crossing of the Bozeman Trail in present Johnson County, was renamed Fort McKinney after the death of Lt. J.A. McKinney in 1876. That site was abandoned in 1878, and the fort’s name moved with the troops to a new site west of present Buffalo, Wyo. The fort closed in 1894, and in 1903 the site was taken over by the Veterans’ Home of Wyoming, which remains in operation there today.

Toomey’s Mills in Newcastle, Wyo., began operations as Newcastle Milling Company and Electrical Light Plant in 1905, producing flour by day and generating electricity at night. In 1919, D. J. Toomey purchased the business and it remained in the family until 1965. In 1974, new owners converted it into a restaurant, the Old Mill Inn. In 1995, current owners, Doug and Larita Brown bought the property, which is listed in the National Register of Historic Places, in 1995.