Devils Peak, also called Mount Diablo or Diablo Peak, rises 2,429 feet on Santa Cruz Island off the Southern California coast. The tallest peak in the Channel Islands, it stands within Channel Islands National Park on land owned by The Nature Conservancy. Its significance extends beyond the island itself: it is the highest mountain on an ocean island in the contiguous United States, exceeding Mount Constitution on Orcas Island by only a few feet. The summit area is not freely open, and access requires a permit.