[2] Santa Cruz Island, the largest of the eight, is divided between The Nature Conservancy and the National Park Service.

As stated in the foundation document:[9] The purpose of Channel Islands National Park is to protect and connect the public to the nationally significant natural, scenic, wildlife, marine, ecological, historical, archeological, cultural, and scientific values of the Channel Islands in the state of California.Radiocarbon dating of a fire area near Arlington Canyon on the northwest coast of Santa Rosa Island shows human habitation from at least 35,000 years BC, while a burned mammoth bone was dated at 28,000 years BC.

Crews took approximately 11 days to seal the rupture using a cement plug, during which approximately 200,000 US gallons (760,000 litres; 170,000 imperial gallons) of crude oil spilled into the Pacific Ocean, creating an oil slick with an area of about 800 square miles (2,100 km2).

[15] It resulted in a 34,000 acres (14,000 ha) expansion of the Department of the Interior buffer zone in the channel and contributed to the formation of the Environmental Protection Agency.

Finally, the distinctive odor of the petroliferous Monterey Shale is evident on the eastern end of Santa Cruz Island.

[11]: 1–2 The islands within the park extend along the Southern California coast from Point Conception near Santa Barbara to San Pedro, a neighborhood of Los Angeles.

[11]: 11–14, 119 Lower Tertiary sequence of rocks are found within the Christi Anticline on the southwestern part of Santa Cruz Island.

The eruptive center is east of Devils Peak, and juxtaposed against the west-northwest trending strike-slip Santa Cruz Island Fault to the south.

These 2400 m of SCI Volcanics have been further subdivide into four members, consisting of the lowermost Griffith Canyon, followed by Stanton Ranch, Devil's Peak, and Prisoner's Harbor, the uppermost.

The 1994 Mammuthus exilis discovery on Santa Rosa near Carrington Point, was the first example of an in situ, almost complete, articulated skeleton.

[26] However, only three land mammals are native to the islands, one of which is the deer mouse (Peromyscus maniculatus) which is known to carry the sin nombre hantavirus.

[28] Other animals in the park include island scrub jay, harbor seal, California sea lion, island night lizard, barn owl, American kestrel, horned lark and meadowlark and California brown pelican.

Marine life ranges from microscopic plankton to the endangered blue whale, the largest animal on earth.

[29] The visitor center contains several exhibits that provide information regarding all five islands, native vegetation, marine life and cultural history.

[4] Channel Islands National Park recreational activities include backpacking, camping, day hiking, scuba diving, and spearfishing.

Channel Islands National Park is renowned for its large number of complex, beautiful sea caves.

Based on ocean conditions and ferry availability, Scorpion Anchorage on Santa Cruz Island is the most visited area in the park for day and camping visitors.

[34] Although most visitation occurs in the summer, migrating gray whales and spectacular wildflower displays attract visitors in the winter and spring.

Autumn is an excellent time to travel to the park, as well as for diving, as the days are usually sunny, with minimal winds and clear ocean water.

It is recommended that inexperienced visitors use caution when visiting the national park due to changing ocean conditions in this unique ecosystem.