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Steep-walled, flat-topped buttes standing 200 to 400 feet above the surrounding prairie, The Castles contains exposed rock of Upper Cretaceous, Paleocene, Oligocene, and Miocene Ages. Cretaceous and Tertiary beds contain a variety of flora and fauna fossils. The site is located within the Custer National Forest.
Location: Harding County, SD
Year designated: 1976
Please remember, National Natural Landmarks (NNLs) are not national parks. NNL status does not indicate public ownership, and many sites are not open for visitation.
Last Updated: June 28, 2012