Santa Cruz Island is located off the southwestern coast of Ventura, California, United States. It is the largest island in California and largest of the eight islands in the Channel Islands archipelago and Channel Islands National Park. Forming part of the northern group of the Channel Islands, Santa Cruz is 22 miles long and 2 to 6 miles wide with an area of 61,764.6 acres.
The island's coastline has steep cliffs, large sea caves, coves, and sandy beaches. The highest point is Devils Peak, at over 2,450 feet. A central valley splits the island along the Santa Cruz Island Fault, with volcanic rock on the north and older sedimentary rock on the south. This volcanic rock was heavily fractured during an uplift phase that formed the island, and over a hundred large sea caves have been carved into the resulting faults. The largest of these is Painted Cave, among the world's largest.
The island is part of Santa Barbara County, California. The 2000 census showed a population of two people. Santa Cruz is the largest privately owned island off the continental United States. Ownership is split between the National Park Service and the Nature Conservancy.