Anacapa Island is a small volcanic island located about 14 miles (23 km) off the coast of Ventura, California, in Ventura County.
Anacapa is part of the Channel Islands archipelago (island chain), and is part of the Channel Islands National Park. It is the smallest of the northern islands. The island is actually composed of three islets: East Island, Middle Island and West Island. Together, the islands are defined by the United States Census Bureau as Block Group 8, Census Tract 36.04 of Ventura County, California. The official 2000 census population was 3 permanent residents (Ranger Station in the eastern part of East Island), and the total land area was 2.947 square kilometres (1.138 sq mi).The highest peak is Summit Peak 2 on West Island, 930 feet (283 m).
East Island's most notable natural feature is Arch Rock, a 40-foot (12 m)-high natural bridge.
Anacapa is the only one of the Channel Islands to have a non-Spanish-derived name. Anacapa comes from the Chumash word eneepah, meaning mirage island.
On the night of December 2, 1853, the sidewheel steamer Winfield Scott running at full speed crashed into the rocks off Middle Anacapa and sank. All of the passengers survived and were rescued after a week.
The United States Coast Guard built a light beacon in 1912 and a light station in 1932 (Anacapa Island Light). It was the last lighthouse built by the United States Lighthouse Service. The lighthouse is located on the eastern part of the island, at the entrance to the Santa Barbara Channel.
On January 31, 2000, Alaska Airlines Flight 261 crashed near the island.
Invasive ship rats (Rattus rattus) are thought to have been introduced to the island from the wrecked ship. They had devastating consequences for the island's seabirds and other native species, but were successfully eradicated in 2001–2002. With the rats gone, the number of rare Xantus' Murrelets has increased more than 80 percent in the last three years. This is one of many recoveries following invasive species eradications from the Channel Islands.
Another invasive species of Anacapa is ice plant (Carpobrotus edulis). The United States Coast Guard introduced the African plant to the island in the 1950s to prevent erosion. The National Park Service has initiated a restoration project to eradicate all of the ice plant by 2016, the centennial of the National Park Service Organic Act.
The rare plant Anacapa Island desert-dandelion (Malacothrix junakii) is known only from the island.
In The Channel Islands of California (1910), Charles Frederick Holder says of Anacapa
Arid appearing, desolate, wind-swept, Anacapa is withal a valuable possession to its owner, and one of the picturesque islands of the entire group. Its strange rocks, moving, passing, intermingling, made a strong impression on my mind, an impression of warring nature, conflicts of wind and rock, of seas eating into its very vitals, of caves that undermine it, and of the old rock fighting for its very life against the sea.