Big Sky is a census-designated place (CDP) in Gallatin and Madison counties in the southwestern part of the U.S. state of Montana. Located immediately west of the Gallatin River and U.S. Route 191, Big Sky is approximately midway between West Yellowstone and Bozeman. The population was 1,221 at the 2000 census. The community is also home to a ski resort of the same name. Big Sky is near the private resort community, Yellowstone Club, which is located west of the town of Big Sky.