South Park, Mountain valley in Park County, United States.

South Park is a grassland flat in Park County, central Colorado, lying between the Mosquito Range to the west and the Rampart Range to the east. It covers about 1,000 square miles (2,600 sq km) around the headwaters of the South Platte River at elevations of roughly 9,000 to 10,000 feet (2,700 to 3,000 m). A paved road curves across the open valley floor, with low bushes and trees scattered across the dry grass.

Ute tribes used the valley for centuries as hunting grounds before European settlers discovered gold and silver deposits in the mid-19th century during the Colorado Gold Rush. Mining activity shaped the development of the region and led to the founding of several settlements.

The South Park City Museum displays buildings and objects from the mining era in faithfully preserved structures. Visitors can see how settlers lived and worked at this elevation.

Several trails run through the valley and offer opportunities for hiking, camping, fishing, and wildlife watching. Access is via U.S. Route 285, which crosses the valley from north to south.

The animated series South Park, launched in the late 1990s, took its name from this valley. Co-creator Trey Parker grew up in Conifer, about 40 miles east of Fairplay, and he and Matt Stone drew on Colorado tales of UFO conspiracies and alien abductions associated with the area.