Bar Nunn is a town in Natrona County, Wyoming, United States. It is a part of the Casper, Wyoming Metropolitan Statistical Area. The population was 2,981 at the 2020 census, a jump of 35% from a population of 2,213 at the 2010 census. It was incorporated in 1980. The town was constructed around the runways of Wardwell Field, Casper's original airport, which was later replaced by Casper–Natrona County International Airport.