Castle Rock has access to thousands of miles of trails including the famous American Discovery Trail which links the east and west coast of the United States. The Official trails in and around Castle Rock lead into Diablo Foothills Regional Park, Walnut Creek Open Space and Mount Diablo State Park. You can even follow the Mokelumne Coast to Crest Trail to the Carquinez Straight in Martinez, CA, a hike roughly 13 miles long. The straight links the waters of the San Francisco Bay to the California Delta. Though the official trail map does not show them, there are many trails in and around the rock formations that have given Castle Rock its name. Part of this area can be seen on the map to the east of Pine Creek. East Bay Regional Park District has chosen to close this area to the public from February 1st to July 31st in an effort to lessen the burden on nesting Peregrine Falcons who call the rocks home.