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Cassia Silent City of Rocks

Cassia Silent City of Rocks
Cassia Silent City of Rocks

Cassia Silent City of Rocks contains monolithic landforms created by exfoliation processes on exposed massive granite plutons. It is the best example of bornhardts (weather-resistant rock left standing after erosion of surrounding rock) in the country.

Location: Cassia County, ID

Year designated: 1974

Acres: 20,214

Ownership: Federal, State, Private

For additional information see:


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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