Custer State Park is a South Dakota State Park and wildlife reserve in the Black Hills, United States. The park is South Dakota's largest and first state park, named after Lt. Colonel George Armstrong Custer. The park covers an area of over 71,000 acres (287 km²) of varied terrain including rolling prairie grasslands and rugged mountains.

The park is home to a herd of 1,500 bison. Elk, coyotes, mule deer, white tailed deer, mountain goats, prairie dogs, bighorn sheep, river otters, pronghorn, cougars, and feral burros also inhabit the park. The park is known for its scenery, its scenic drives (Needles Highway and the wildlife loop), with views of the bison herd and prairie dog towns. This park is easily accessible by road from Rapid City. Other nearby attractions are Wind Cave National Park, Mount Rushmore, Jewel Cave National Monument, Crazy Horse Memorial, and Badlands National Park.