Red Rocks Park in Jefferson County, Colorado, is a Denver mountain park and historic district known for its dramatic red sandstone outcrops and the designed landscape built around them. The rocks, part of the Fountain Formation, were created about 290 to 296 million years ago and later tilted during the Laramide orogeny. Long used by the Ute as a sheltered campsite, the area was later developed as a private park in the late 19th century before Denver acquired it in 1928. During the Depression, Civilian Conservation Corps crews built much of the park’s roads and amphitheater, helping shape a site that combines striking geology, recreation, and a major cultural venue.