The Red River Gorge is a canyon system on the Red River in east-central Kentucky. Geologically it is part of the Pottsville Escarpment. The gorge lies within the Daniel Boone National Forest and was subsequently designated the Red River Gorge Geological Area, an area of around 29,000 acres (12,000 ha; 120 km2; 45 sq mi). It was designated a National Natural Landmark and National Archaeological District, and listed on the National Register of Historic Places. The 13,379-acre (5,414 ha; 54.14 km2; 20.905 sq mi) Clifty Wilderness Area lies entirely within the geological area in the Red River Gorge.