Anacapa Island

Anacapa Island is almost five miles long, but only 1/4/ to ½ mile wide. It is actually composed of three islets: East, Middle and West and bounded on most sides by sheer cliffs and connected only occasionally at extremely low tides. Together, the three islets are 1.1 square miles in size and contain approximately 700 acres. Anacapa Island is only slightly larger than Santa Barbara Island, making it the second smallest of the eight California Channel Islands. Anacapa Island is eleven miles from the mainland, and its highest point is Summit Peak on West Anacapa at 930 feet in elevation.

Flora and Fauna:

Coastal bluff, island grassland and coastal sage scrub are found on all three islets. In addition, West Anacapa has chaparral and woodland communities. The flora of Anacapa Island contains over two hundred different native and introduced plants. Some are rare and endangered. Unlike similarly sized Santa Barbara Island, Anacapa Island supports a number of trees and shrubs, particularly in the canyons on West Anacapa.

The native deer mouse (Peromyscus maniculatus anacapae) is an endemic subspecies found on all three islets and in all habitats.

Physiography and Geology:

Anacapa Island is predominantly volcanic in origin, composed mainly of highly weathered Miocene volcanic rock that has been eroded by wind and waves. It was probably uplifted not by volcanic activity, but by faulting, many submarine lava flows can be seen on the island. In a few locations, sedimentary rocks can be found, including the blue-green San Onofre breccia on the south shore of West Anacapa near Cat Rock. Fissures forming sea caves and blowholes are common. Visually, Anacapa Island, along with the other Northern Channel Islands, represents a seaward extension of the Santa Monica Mountains.

Arch Rock, the easternmost extension of Anacapa Island, is a natural bridge formed by sea erosion. This forty-foot-high arch is considered by many to be the Anacapa Island trademark