Nature: California Islands

Island | Description

Anacapa Island

Located 14 miles off the coast of Ventura, California. It contains 728 acres of land spread across three mountainous islets. The island has only three permanent residents.

Begg Rock

Begg Rock A 15-foot high rock, located 8 miles from San Nicolas Island.

Prince Island

Located near San Miguel Island and measures about 35 acres.

San Clemente Island

Southernmost Channel Island, containing 56.81 square miles of land. It is 24 miles long, and uninhabited. An active U.S. Navy base is located on the island.

San Miguel Island

Westernmost Channel Island, measuring 8 miles long, 3.7 miles wide, and containing 9,325 acres of land. The island is uninhabited, and is rarely visited.

San Nicolas Island

Is said to be the most remote island of the Channel Islands, and is used by the U.S. Navy as a weapons testing and training facility. It has no civilian inhabitants, but is inhabited by military personnel. It covers 14,562 acres.

Santa Barbara Island

Smallest Channel Island at 640 acres in area; it is located roughly between San Nicolas and Santa Catalina Islands.

Santa Catalina Island

The most inhabited of the Channel Islands, with a population of 3,696 as of 2000. It is about 22 miles long with a maximum width of 8 miles. It covers 74.98 square miles.

Santa Cruz Island

Santa Cruz Island measures 22 miles long with an average width of 4 miles, covering 96.5 square miles. It is the largest Channel Island. The island is now on public land, but was previously the largest privately owned island of the continental United States.

Santa Rosa Island

Santa Rosa Island occupies 83.1 square miles (215 km2)

, and is the second largest Channel Island. The island has a permanent population of 2 persons, and is about 26 miles off the coast of Santa Barbara, California.

Shag Rock

Small islet located off the north shore of Santa Barbara Island, and is only about 1 acre.

Sutil Island

Located off the southwest shore of Santa Barbara Island, and is about 12 acres. It is named for a Spanish ship exploring the West Coast in an expedition led by Sebastián Vizcaíno.

Farallon Islands

The Farallon Islands are a group of rugged small islands over 20 miles offshore from the city of San Francisco. They consist of over twenty small islets divided into north, south and middle sections, as well as a major bank, Fanny Shoal. The surrounding waters were once used as a disposal site for radioactive waste.

Southeast Farallon

Is the largest of the Farallons, covering 0.19 square miles. It is the only inhabited Farallon Island, and is also the site of Farallon Island Light.

Seal Rock

Small islet south of Southeast Farallon Island, with a maximum height of 82 feet .

Maintop Island 

West of Southeast Farallon Island, and has a maximum height of 223 feet.

Drunk Uncle Islets Group of small islets north of Maintop Island.

Aulone Island and Great Arch Rock 

North of Southeast Farallon Island, measuring 200 feet wide and 400 fee long.

Sugarloaf Island

Directly to the northeast of Aulone and Great Arch Rock, about 80 feet high.

Sea Lion Rock

Small islet northwest of Aulon Island, about 130 feet long.

Middle Farallon Island

Medium-sized islet 1.8 miles northwest of Southeast Farallon Island. It is 210 feet long and has an area of 0.8 acres.

North Farallon Island (North Farallon)

Medium-sized islet 500 feet long and 100 feet high, covering 2 acres.

Island of St. James 

Medium-sized islet 3 acres in size, measuring 410 feet long and 154 feet high.

Piedra Guadalupe

Peñasco Quebrado

Farallón Viscaíno

Fannette Island

Lake Tahoe The only major island in Lake Tahoe, located within Emerald Bay.

Main Island

Lake Casitas A 1.5 miles long, 850-foot high island rising 512 feet above the lake surface.

Mullet Island

Salton Sea

A small volcanic island near the southern end of the Salton Sea near the mouth of the Alamo River

Negit Island

Mono Lake A young volcanic cone, connected to the mainland during low water. It is an important stop for nesting birds, and as a result is closed to visitation during April.

Paoha Island

Mono Lake 2.5 miles long and 2 miles wide, and is the largest Mono Lake island.

Rattlesnake Island

Clear Lake A 53-acre island desired by the Elem Indian Colony.

Red Island Salton Sea A volcanic island near the southern end of the sea, on the San Andreas Fault.

Island Chaffee

An artificial island/oil platform named after astronaut Roger B. Chaffee who died in the Apollo 1 accident. Located in San Pedro Bay.

Deadman's Island

Terminal Island

A former island in Los Angeles Harbor, removed in 1928; sometimes referenced as Isla Del Umberto, and Reservation Point

Freeman Island

An artificial island/oil platform named after astronaut Theodore Freeman who died in a crash. Located in San Pedro Bay.

Island Grissom

An artificial island/oil platform named after astronaut Gus Grissom who died in the Apollo 1 accident. Located in San Pedro Bay.

Terminal Island

An artificial island shared between the cities of Los Angeles and Long Beach. It is 3.5 miles long and covers an area of 4.46 square miles.

Island White

An artificial island/oil platform named after astronaut Edward Higgins White who died in the Apollo 1 accident; Located in San Pedro Bay.

Indian Island

Woodley Island (Indian ) An island 1.3 miles long, associated with the Wiyot people.

Newport Bay

The bay associated with Newport Harbor and the city of Newport Beach, California.

Balboa Island

A 120-acre, densely populated harbor island with 1,500 homes. Partially created as a result of the Santa Ana River flooding in 1824, then artificially expanded to its present size.

Harbor Island

Bay Island

West of Balboa Island

Lido Isle

Northwest of Balboa Island.

Linda Isle

North of Harbor Island.

Sacramento-San Joaquin River Delta


Andrus Island

Sacramento 7,400-acre island, bounded by Sacramento River, Georgiana Slough, Mokelumne River, San Joaquin River, Jackson Slough, and Seven Mile Slough.

Bacon Island

San Joaquin 5,400-acre island, bounded by Connection Slough, Old River, Woodward Island, and Middle River

Bethel Island

Contra Costa 3,600-acre island, bounded by Taylor Slough, Piper Slough, Sand Mound Slough, and Dutch Slough

Bouldin Island

San Joaquin 5,900-acre island bounded by South Mokelumne River, Little Potato Slough, Potato Slough, and Mokelumne River.

Bradford Island

Contra Costa 2,190-acre island in the lower delta bounded by the San Joaquin River, False River and the Bradford Island canal/slough. Accessible only by Ferry via Jersey Island, just south of it.

Browns Island

Contra Costa 680-acre island, bounded by Middle Slough, New York Slough, and Suisun Bay

Jersey Island 

Contra Costa 3,520-acre island, bounded by False River, Piper Slough, Taylor Slough, Dutch Slough and San Joaquin River.

Jones Tract (Upper Jones Tract - Lower Jones Tract)

San Joaquin 12,000-acre island (tracts, Upper- and Lower-), bounded by Empire Cut, Whiskey Slough, Trapper Slough, and Middle River, 10 km east of Stockton

King Island

San Joaquin 3,200-acre island bounded by White Slough, Bishop Cut, Disappointment Slough, and Honker Cut

Kings Island

Contra Costa 8.6-acre island in Old River

McDonald Island

San Joaquin 5,900-acre island , bounded by San Joaquin River, Middle River, Latham Slough, and Empire Cut.

Ryer Island

Solano 11,700-acre, bounded by Miner Slough and Steamboat Slough.

Sherman Island

Sacramento 14,000-acre island bounded by the Sacramento River, Three Mile Slough, and the San Joaquin River.

Staten Island

San Joaquin 9,100-acre island bounded and flanked by the North Mokelumne River and South Mokelumne River.

Twitchell Island

Sacramento 7,400-acre, bounded by Seven Mile Slough, San Joaquin River, and Three Mile Slough

Venice Island

San Joaquin 1,250-hectare (3,100-acreisland bounded by Potato Slough, Little Connection Slough, Stockton Deepwater Channel Venice Cut, and San Joaquin River.

Victoria Island

San Joaquin 7,200-acre island bounded by North Victoria Canal, Middle River, Victoria Canal, and Old River.

West Island


Winter Island

Contra Costa

Woodward Island 

San Joaquin 1,790-acre island bounded by Bacon Island, Old River, Middle River, and Woodward Canal

Other islands of the Bay Area:

Alameda Island 

Alameda, San Francisco (small, uninhabited sliver) This 6-mile long island in San Francisco Bay is the main part of the City of Alameda.

Alcatraz Island  

San Francisco This 22-acre island in San Francisco Bay once served as a lighthouse, a military fortification, a military prison, and as a federal prison until 1963. It is now part of the Golden Gate National Recreation Area.

Angel Island 

Marin With an area of 1.2 square miles, this island in San Francisco Bay processed approximately 1 million immigrants to the U.S. during 1910 to 1940. It is currently a state park.

Año Nuevo Island

San Mateo Small Pacific island, about 0.2 miles long, near Año Nuevo (New Year's) Point, south of the Golden Gate. It is protected by the Año Nuevo State Reserve as an important habitat for seabirds and other coastal wildlife.

Bair Island 

San Mateo This 2,600-acre island in San Francisco Bay near Redwood City is part of the Don Edwards San Francisco Bay National Wildlife Refuge.

Bay Farm Island

Alameda This former island in San Francisco Bay has been connected to the mainland. It is part of the City of Alameda.

Belvedere Island 

Marin This former island in Richardson Bay has been connected to the mainland. It is part of the City of Belvedere.

Bird Island

Marin Small Pacific island between Point Bonita and Rodeo Cove.

Bird Rock

Marin Small Pacific island west of Tomales Point, primarily a seabird colony. It covers 2 acres.

Brooks Island 

Contra Costa A 65-acre island in San Francisco Bay south of Richmond, protected as part of the Brooks Island Regional Shoreline.

Brother Islands

Contra Costa This pair of islands is located west off Point San Pablo in Richmond. Each is about 300 feet (91 m)

long. East Brother has a lighthouse and a bed and breakfast.

Castro Rocks 

Contra Costa Beneath the Richmond - San Rafael Bridge.

Coast Guard Island 

Alameda Located in the Oakland Estuary, this 67-acre artificial island is part of the City of Alameda. It is home to various United States Coast Guard facilities.

Corinthian Island 

Marin This former island was joined to the mainland in the 1980s. It is split between the city of Belvedere and the town of Tiburon.

East Marin Island

Marin Near San Rafael, California.

Gull Rock  

Marin A Pacific island near Mount Tamalpais, about 200 feet long.

Hog Island

Sonoma Island in the Petaluma River wetlands.

Hog Island

Marin A 2-acre island in Tomales Bay.

Kent Island 

Marin An island in Bolinas Lagoon, near the town of Bolinas. About 0.5 miles  long.

Mare Island 

Solano An island in San Pablo Bay near Vallejo. About 3.5 miles  long, site of a major shipyard.

Mussel Rock

San Mateo A stack in the Pacific Ocean near Daly City. About 200 feet (61 m) long.

Rat Rock                                                              

Marin An 18-foot tall rock north of China Camp.

Red Rock I

Contra Costa, Marin and San Francisco This uninhabited 5.8-acre island is located in San Francisco Bay just south of the Richmond - San Rafael Bridge, near the meeting point of three counties. It is privately owned.

San Pedro Rock

San Mateo A Pacific island near the city of Pacifica. About 800 feet long.

Seal Rocks

San Francisco A series of large rocks in the Pacific Ocean that host a sea lion colony.

Seal Rock

San Mateo A Pacific island south of Half Moon Bay, about 500 feet long.

Sears Rock

Marin A rock in the Centissima Reef.

The Sisters

Marin A pair of small islands in San Pablo Bay, 2,000 feet south of Point Saint Pedro.

Treasure Island 

San Francisco This 403-acre artificial island in San Francisco Bay is tied to Yerba Buena Island. It was dredged out of the bay to house the Golden Gate International Exposition of 1939-40.

West Marin Island 

Marin Near San Rafael, California.

Yerba Buena Island

San Francisco This island in San Francisco Bay is home to a Coast Guard station. The San Francisco - Oakland Bay Bridge passes through it by means of a tunnel.

Suisun Bay

Chipps Island 


Dutton Island


Freeman Island 


Grizzly Island 


Hammond Island


Joice Island 

Solano A marshy island 6 miles long, north of Grizzly Bay.

Morrow Island 


Roe Island 

Solano In Suisun Bay.

Ryer Island 

Solano  1,170-acre island, between Suisun Bay and Suisun Cutoff. About 2 miles long.

Seal Islands (Seal Islands)

Contra Costa In Suisun Bay.

Simmons Island 


Snag Island 


Van Sickle Island

Solano An island 2.5 miles long at the junction of the Sacramento River, San Joaquin River, and Suisun Bay.

Wheeler Island


Rincon Island Rincon

A 1 acre artificial island off the coast of Ventura County, leased for oil and gas production.

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