For the more information about the air resources of the National
Park Service, please visit http://www.nature.nps.gov/air/.
Comprised of deep erosion canyons with rugged rims, Rainbow
Basin is an outstanding example of geologic processes. The site
contains significant fossil evidence of insects, larger Miocene
mammals and mammal tracks. Location: San Bernardino County, CA
Year designated: 1966 For additional information see: 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