The island's coastline has steep cliffs, large sea caves, coves, and sandy beaches.

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.

[4][7] The Chumash people who lived on the island developed a highly complex society dependent on marine harvest, craft specialization, and trade with the mainland population.

Finally, in 1769, the land-and-sea expedition of Don Gaspar de Portolà reached Santa Cruz Island.

When Mission San Buenaventura was founded across the channel in 1782, the slow religious conversion of the Santa Cruz Chumash commenced.

On the next day, the Chumash returned a staff topped by an iron cross, which the Spanish had inadvertently left behind.

[4][9]: 100 Governor Juan Alvarado made a Mexican land grant of the Island of Santa Cruz to his aide Captain Andrés Castillero in 1839.

He imported cattle, horses, and sheep to the island and erected one of the earliest wharves along the California coast at Prisoners' Harbor.

[4][9]: 102–103  Barron sold the island for $150,000 in 1869, and Shaw left for San Francisco and Los Alamos, where he continued ranching.

He then implemented his vision of building a self-sustaining sheep and cattle ranch, vineyard, and a nut and fruit grove operation on the island.

The operation received water from four springs, El Pato, Gallina, The Dindos, and The Peacock, which fed into a 26,000-US-gallon (98,000 L) reservoir, tanks, and dams.

Justinian Caire's will stipulated that his two sons, Arthur and Frederic, were to be executors of his will and continue managing operations with little change.

The married daughters' families, led by in-law Ambrose Gherini, retained 6,000 acres (2,450 hectares) on the island's east end.

After trying for a short time to continue the sheep operation, bringing in 10,000 head, he decided to switch to beef production.

While retaining most of the 19th-century structures dating from the Caire period, Stanton constructed a few buildings to meet the needs of his cattle ranch, the most notable of which is Rancho del Norte on the isthmus.

Protracted litigation between the Gherinis and the federal government started in 1980 when Channel Islands National Park was designated.

However, the purchase was held up as family members pushed the federal government to pay what they believed was the appropriate amount.

The real property passed to The Nature Conservancy through a prior agreement that Carey Stanton had established with the non-profit organization.

[17] The Nature Conservancy rapidly liquidated the cattle operation and ended the ranching era on the island.

The remaining land, known as the Santa Cruz Island Reserve, is used for scientific research and education and is managed by a combination of organizations, including The Nature Conservancy, the University of California Natural Reserve System, and the Santa Cruz Island Foundation.

The Channel Islands often provided smugglers and bootleggers with convenient yet isolated hideaways to store their goods.

During the Cold War a communications station was installed as a part of the Pacific Missile Range Facility.

Where sheep grazing was prevalent, the native plant cover has been damaged, and erosion and gullying has been a problem in some areas.

Because of eggshell thinning caused by DDT and other factors, successful bald eagle nesting in the northern Channel Islands ended by 1949.

Santa Cruz Island has several airstrips, all operated by The Nature Conservancy: This article incorporates public domain material from websites or documents of the National Park Service.