City (pop., 2000: 49,644), east-central Wyoming, U.S., on the North Platte River. Founded in 1888, it was located on the Oregon Trail and the Pony Express route. The discovery of oil in the 1890s began an oil boom, and the oil fields of the Teapot Dome scandal were nearby. Casper's economy is based on the production of oil and natural gas and the manufacture of oil-field equipment. Mining (uranium, coal, bentonite) and cattle and sheep raising also are important.