Casper is a city in and the county seat of Natrona County, Wyoming, United States. Casper is the second-largest city in Wyoming, according to the 2010 census, with a population of 55,316. Only Cheyenne, the state capital, is larger. Casper is nicknamed "The Oil City" and has a long history of oil boomtown and cowboy culture, dating back to the development of the nearby Salt Creek Oil Field. In 2010, Casper was named the highest-ranked family-friendly small city in the West, and ranked eighth overall in the nation in Forbes magazine's list of "the best small cities to raise a family".
Casper is located in east-central Wyoming at the foot of Casper Mountain, the north end of the Laramie Mountain Range, along the North Platte River.