The largest of all the Channel Islands, Santa Cruz Island, is made up of over 60,000 acres, and is located 19 miles off the coast of Ventura. Containing rugged mountain ranges, deep canyons, sea caves, coastline cliffs, tidepools, beaches, and year-round springs and streams, the island of Santa Cruz is a diverse environment. Picacho Diablo, the islands highest peak at 2,434 feet, is one of many high peaks on the island. Between two mountain ranges is a large valley that covers most of the islands length and can be accessed through a three mile canyon filled with streams. Also found on Santa Cruz is Painted Cave, the largest and deepest known sea cave in the world. Another interesting point on the island is the mysterious wreck at Scorpion Bay of what is thought to be the coastal minesweeper Peacock. An attempt at salvaging the ship was unsuccesful, and the wreck came to rest at its present location due either to storm or intentional sinking. Along with diverse topography, there are also many different biomes of flora on the island including marshes, grasslands, and pine forests. Inhabiting these areas are over 600 different species of plants including eight found nowhere else in the world. With a topographically varied Mediterranean climate, the island of Santa Cruz sustains over 140 different species of land birds, marine mammals, and other life. The western 90% of Santa Cruz island is owned and operated by The Nature Conservancy, with the eastern 10% owned by the National Park Service. The Chumash called the island "Limuw", meaning "In the Sea", and it was the most populated of the four northern islands at the time of the missions, possibly sustaining a population of over 1,000. The natives were skilled at making the shell beads which the Chumash used as money, and manufactured much of the beads used on the mainland. The word Chumash is in fact believed to have been derived from "michumash", a name for the Santa Cruz Islanders in one of the mainland languages which probably meant "makers of shell bead money". Santa Cruz Island was obviously very important to Chumash, for it was believed that the mother goddess Hutash first created humans on that very island.

The modern name of Santa Cruz came into existence with a story of it's own. When the Spanish explored the island originally in 1769, a franciscan priest with the sea going expedition led by Juan Perez went ashore at what is now called Prisoner's Cove. The priest is said to have forgotten his walking staff which was tipped with an iron cross, and giving it up, was surprised when the native Chumash returned it to him the next day. From this, the island was named Isla de Santa Cruz, or "Island of the Holy Cross". The kindness of the Chumash was later responded to by the hostility and oppression of the Spanish mission system.