Access to Anza - Borrego Desert State Park Campgrounds South of highway. With over 600,000 acres, Anza-Borrego Desert State Park is the largest state park in California. With 12 wilderness areas and miles of hiking trails provide visitors with an unparalleled opportunity to experience the wonders of the Colorado Desert. Camping: Family Campsites, Group Campsites, Campers (Max. Length) 35', Picnic Areas, Restrooms, RV Hookups, RV Dump Station.