- Six Flags Frontier City
- Gully Washer
Frontier City is a western-themed amusement park in Oklahoma City. It is owned by EPR and operated by Six Flags. The park originally opened in 1958. Frontier City is the third-oldest Six Flags park behind Six Flags New England and Six Flags Great Escape and Hurricane Harbor. Frontier City—and La Ronde in Montreal, Canada, are the only two company parks not officially branded as Six Flags parks.