For the more information about the air resources of the National Park Service, please visit http://www.nature.nps.gov/air/.
Onyx cave, located within Coronado National Forest, is considered to be the finest cave in Arizona. Helictites and speleothems, such as shields are numerous and beautifully developed.
Location: Santa Cruz County, AZ
Year designated: 1974
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