Castles & Capitol Rock, Sioux R.D.

The Castles and Capitol Rock National Natural Landmarks (NNL) contain exposed rock of Upper Cretaceous, Paleocene, Oligocene and Miocene Ages.  Designated first in 1976, (U.S.F.S Federal Ownership), two natural landmarks dot the South Dakota sky in Harding County on the Sioux Ranger District, Custer Gallatin National Forest. 

Whether looking for a day trip or to spend a long weekend in beauty and solitude you’ll likely enjoy discovering the fascinating geological formations across the eight units on the Sioux Ranger District.

Adjacent to Reva Gap Campground, the Castles, a registered natural landmark consisting of steep-walled flat-topped buttes rising 200 – 400 feet above the rolling prairie offers an exceptional peek at our nation’s natural heritage.  The Castles and Capitol Rock Natural Landmarks are significant due to the variety of rock ages illustrated by the towering buttes.

Disclaimer:  Active mine reclamation is in progress on the Sioux Ranger District.  Visitors need to know and understand acceptable exposure levels.  Read about Erionite, before you go.