Upton, Wyo., known originally as Irontown or Iron City, and later as Merino, began in 1890 as a Burlington Railroad depot near a set of sheep corrals. The town was not incorporated until 1909. The Burlington’s successor, the BNSF, remains an important employer today, as do the school district and a clinic operated by Weston County Health Services.

The history of nuclear weapons in Wyoming is intimately connected to the F. E. Warren Air Force Base, which in turn is tied to the global development of rocketry and nuclear might. If Wyoming were a nation, Warren AFB in Cheyenne would make it one of the world’s major nuclear powers. Its history with nuclear weapons in Wyoming is tied closely to the worldwide tensions of the Cold War, and with the development of missile-based nuclear weapons systems.

Home to 19 of Wyoming’s first families, the Historic Governor’s Mansion was occupied from 1904 through 1976, opened to the public in 1977 and extensively renovated in 2004.

The abundant vertebrate fossils of the Green River formation in western Wyoming have been known to science since the 1860s. Most are fish, buried in lime-rich mud at the bottom of freshwater lakes about 50 million years ago. Fossil Butte National Monument, west of Kemmerer, Wyo. was created by Congress in 1973 to protect a site extremely rich in these fossils.

The story of uranium in Wyoming is a high-stakes drama whose cast includes fever-driven prospectors, ranchers defending their property rights, government officials intent on national security, entrepreneurs, engineers and world-class mining companies.

Wyoming's fossils have been important to science since the 1870s and continue to be useful today. Remains of Triceratops, Diplodocus, Tyrannosaurus and others have helped answer—and raise—many questions about the ancient history of the planet and have captured popular imagination with their size or fierce appearance. The scientific value of these fossils and the public interest in them has brought collectors who excavate fossils and ship them to museums all over the country for further study and display. Only a few major finds from Wyoming have remained in the state.

Old West adventurer, orator, barber, reported bigamist, and passionate defender of civil rights, Kentucky-born William Jefferson Hardin was Wyoming’s first African-American legislator in its territorial days.

Fort Phil Kearny, near present-day Story, Wyo., was established by the U.S. Army in the summer of 1866 to protect travelers on the Bozeman Trail from Indian attack. and abandoned two years later, under terms of the1868 Treaty of Fort Laramie. Indians burned the fort shortly after the army left.

Established by mountain men Jim Bridger and Louis Vasquez in 1843, Fort Bridger was an important rest and re-supply spot for emigrants bound to Utah, California and Oregon. Mormons acquired the site in the mid-1850s, and burned it in 1857 as the U.S. Army approached during the bloodless Utah War. The following year the Army took over, and garrisoned the fort until 1890. Today it is a state historic site.

The U.S. Army established Platte Bridge Station in 1862 to protect the Oregon/California/Mormon Trail crossing of the North Platte River and the new transcontinental telegraph. After Lt. Caspar Collins was killed there by Cheyenne and Lakota Indians in 1865, the post was renamed Fort Casper, misspelling his first name. The fort was abandoned two years later, but reconstructed in 1936—and renamed Fort Caspar—with funds from the Works Progress Administration. Fort grounds and a museum are open to the public.