Toadstool Geologic Park, in the Oglala National Grassland in northeastern Sioux County, is a badlands of eroded clay and sandstone "toadstools" with fossil tracks. A 1-mile interpretive loop starts at the campground, which has 12 sites ($15 a night in 2026, $3 day use), vault toilets and no drinking water; a replica sod house was built in 1984, and the 3-mile Bison Trail leads to Hudson-Meng. From Crawford take NE 2 north 4.2 miles, Toadstool Road 11.4 miles and Forest Road 902 1.4 miles; roads are very hard to drive when wet. Managed by the Pine Ridge Ranger District, Chadron.