Santa Rosa Island is the second largest of the Channel Islands of California at 53,195 acres. Santa Rosa is located about 26 miles (42 km) off the coast of Santa Barbara, California in Santa Barbara County and is part of Channel Islands National Park.

The Channel Islands are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. They define the Santa Barbara Channel, which sits between the islands and the California mainland. The four Northern Channel Islands are part of the Transverse Ranges geologic province, and the four Southern Channel Islands are part of the Peninsular Ranges province. Five of the islands are within the Channel Islands National Park, and the waters surrounding these islands make up Channel Islands National Marine Sanctuary. The Nature Conservancy was instrumental in establishing the Channel Islands National Marine Sanctuary.