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.

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.

Como Bluff in Carbon County and Albany County, Wyo., is the location of one of the world’s richest quarries of Jurassic dinosaur bones. Paleontologists found excellent dinosaur fossils in greater quantity here in the late 19th century than had ever been known before. These included Allosaurus, Diplodocus and Apatosaurus. Many of these specimens are still on display at the Peabody Museum at Yale University, the Smithsonian Institution’s National Museum of Natural History in Washington, D.C., and the American Museum of Natural History in New York City. The site is seldom quarried today, as most of the bones have been removed. Como Bluff is listed on the National Register of Historic Places.

The Connor Battlefield is a park on Tongue River in Ranchester, Wyo., marking the spot where Brig. Gen. Patrick Connor and about 475 U.S. troops and Pawnee scouts in August 1865 attacked a village of 500 Arapaho under the leadership of Black Bear and Old David. The Arapaho suffered 33 killed, and the troops burned their lodges and drove off most of the horse herd. Today the park offers picnic grounds, a campground and a monument to the event.

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.

On Aug. 29, 1865, troops under Brig. Gen. Patrick E. Connor attacked an Arapaho village near present Ranchester, Wyo. Connor’s detachment was part of a large expedition ordered to subjugate the warring Cheyenne, Sioux and Arapaho in the Powder River Basin. Overall success was mixed. Connor was relieved of his command.

The final Wyoming Territorial Legislative Assembly created Weston County in March 1890. Thirty years later, the discovery of oil at Osage, Wyo., halfway between the county seat of Newcastle and the small town of Upton, led to a number of cyclical economic booms and busts. Today, the county’s industries include agriculture and oil refining.

Remains of at least seven mammoths, probably from a meat cache dating back more than 11,000 years, were found when the Colby Mammoth site east of Worland, Wyo., was excavated by a crew under Wyoming State Archaeologist George Frison in the 1970s.

The White Mountain Petroglyphs in the Red Desert north of Rock Springs, Wyo., feature hundreds of images carved into a rock face between 1,000 and 200 years ago. The site is on Bureau of Land Management land, and is open to the public.

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.