List of islands of California

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This list of islands of California is organized into sections, generally arranged from north to south. The islands within each section are listed in alphabetical order.

The Geographic Names Information System (GNIS) lists 527 named islands in the state.

Humboldt County

Offshore

Island	Image	Coordinates	Description
Sugarloaf Island,			Sugarloaf Island, offshore Cape Mendocino, rises 128 feet (39 m) above mean sea level. It is a special zone in the South Cape Mendocino State Marine Reserve and is closed to public access. Being offshore of Cape Mendocino, the westernmost point in California, Sugarloaf Island is called the westernmost island in the state.

Humboldt Bay

All three islands in Humboldt Bay are located in the narrow midsection of the bay. This portion of the bay is located within the City of Eureka, California entirely within Humboldt County.

Island	Image	Coordinates	Description
Daby Island			The smallest of the three islands within Humboldt Bay, Daby Island has a maximum elevation of 3 feet (0.91 m) and is located slightly northeast of Woodley Island.
Indian Island			The largest island, 1.3 miles (2.1 km) long, was originally the center of culture and population of the indigenous Wiyot people. Now protected, no public access is allowed, except for the Wiyot and grandfathered residents.
Woodley Island			The second largest of the three islands within Humboldt Bay contains: the Woodley Island Marina (Eureka's largest marina), the Eureka regional office of the National Weather Service, and offices of the Humboldt Bay Harbor Recreation & Conservation District.

San Francisco Bay Area

For the Farallon Islands, see List of islands of California § Farallon Islands.

For islands in the Sacramento River Delta, see List of islands of California § Sacramento-San Joaquin River Delta.

For islands in Suisun Bay, see List of islands of California § Suisun Bay.

Other islands of the San Francisco Bay Area:

Island	Image	Coordinates	Counties	Description
Alameda Island			Alameda, San Francisco (small, uninhabited sliver)	This 6-mile (9.7 km) long island in San Francisco Bay is the main part of the City of Alameda.
Alcatraz Island			San Francisco	This 22-acre (8.9 ha) 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 (3.1 km2), 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 (0.32 km) 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 (1,100 ha) 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 (0.81 ha).
Brooks Island			Contra Costa	A 65-acre (26 ha) island in San Francisco Bay south of Richmond, protected as part of the Brooks Island Regional Shoreline.
The Brothers			Contra Costa	Two small islands, East Brother and West Brother, located west of Point San Pablo. 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 (27 ha) 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 (61 m) long.
Hog Island (Petaluma River)			Sonoma	Island in the Petaluma River wetlands.
Hog Island (Tomales Bay)			Marin	A 2-acre (0.81 ha) island in Tomales Bay.
Kent Island			Marin	An island in Bolinas Lagoon, near the town of Bolinas. About 0.5 miles (0.80 km) long.
Mare Island			Solano	An island in San Pablo Bay near Vallejo. About 3.5 miles (5.6 km) 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 (5.5 m) tall rock north of China Camp.
Red Rock Island	90px		Contra Costa, Marin and San Francisco	This uninhabited 5.8-acre (2.3 ha) 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 (240 m) long.
Seal Rocks (San Francisco, California)	90px		San Francisco	A series of large rocks in the Pacific Ocean that host a sea lion colony.
Seal Rock (San Mateo County, California)			San Mateo	A Pacific island south of Half Moon Bay, about 500 feet (150 m) 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 (610 m) south of Point Saint Pedro.
Treasure Island			San Francisco	This 403-acre (163 ha) 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.

Farallon Islands

The Farallon Islands are a group of rugged small islands over 20 miles (32 km) offshore from the mainland of the City and County of San Francisco, which they are also formally within. 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.

Island	Image	Coordinates	Description
Aulone Island and Great Arch Rock			North of Southeast Farallon Island, measuring 200 feet (61 m) wide and 400 feet (120 m) long.
Drunk Uncle Islets			Group of small islets north of Maintop Island.
Farallón Viscaíno
Middle Farallon Island			Medium-sized islet 1.8 miles (2.9 km) northwest of Southeast Farallon Island. It is 210 feet (64 m) long and has an area of 0.8 acres (0.32 ha).
North Farallon Island			Medium-sized islet 500 feet (150 m) long and 100 feet (30 m) high, covering 2 acres (0.81 ha).
Peñasco Quebrado
Piedra Guadalupe
Island of St. James			Medium-sized islet 3 acres (1.2 ha) in size, measuring 410 feet (120 m) long and 154 feet (47 m) high.
Sea Lion Rock			Small islet northwest of Aulon Island, about 130 feet (40 m) long.
Seal Rock			Small islet south of Southeast Farallon Island, with a maximum height of 82 feet (25 m).
Maintop Island			West of Southeast Farallon Island, and has a maximum height of 223 feet (68 m).
Southeast Farallon Island			Is the largest of the Farallons, covering 0.19 square miles (0.49 km2). It is the only inhabited Farallon Island, and is also the site of Farallon Island Light.
Sugarloaf Island			Directly to the northeast of Aulone and Great Arch Rock, about 80 feet (24 m) high.

Suisun Bay

Suisun Bay is an arm of the San Francisco Bay estuary which connects the Sacramento and San Joaquin rivers to the Carquinez Strait.

Island	Image	Coordinates	County	Description
Chipps Island			Solano
Dutton Island			Solano
Freeman Island			Solano
Grizzly Island			Solano
Hammond Island			Solano
Joice Island			Solano	A marshy island 6 miles (9.7 km) long, north of Grizzly Bay.
Morrow Island			Solano
Roe Island			Solano	In Suisun Bay.
Ryer Island			Solano	475-hectare (1,170-acre) island, between Suisun Bay and Suisun Cutoff. About 2 miles (3.2 km) long.
Seal Islands			Contra Costa	In Suisun Bay.
Simmons Island			Solano
Snag Island			Solano
Van Sickle Island			Solano	An island 2.5 miles (4.0 km) long at the junction of the Sacramento River, San Joaquin River, and Suisun Bay.
Wheeler Island			Solano

Sacramento-San Joaquin River Delta

The Sacramento-San Joaquin River Delta is an inverted delta at the juncture of the Sacramento and San Joaquin rivers. There are about 57 named islands in the Delta.

Island	Image	Coordinates	County	Description
Andrus Island			Sacramento	3,000-hectare (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	2,200-hectare (5,400-acre) island, bounded by Connection Slough, Old River, Woodward Island, and Middle River
Bethel Island			Contra Costa	1,450-hectare (3,600-acre) island, bounded by Taylor Slough, Piper Slough, Sand Mound Slough, and Dutch Slough
Bouldin Island			San Joaquin	2,400-hectare (5,900-acre) island bounded by South Mokelumne River, Little Potato Slough, Potato Slough, and Mokelumne River.
Bradford Island			Contra Costa	885-hectare (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	275-hectare (680-acre) island, bounded by Middle Slough, New York Slough, and Suisun Bay
Jersey Island			Contra Costa	1,425-hectare (3,520-acre) island, bounded by False River, Piper Slough, Taylor Slough, Dutch Slough and San Joaquin River.
Jones Tract		upper: lower: (lower)	San Joaquin	4,900-hectare (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	1,300-hectare (3,200-acre) island bounded by White Slough, Bishop Cut, Disappointment Slough, and Honker Cut
Kings Island			Contra Costa	3.5-hectare (8.6-acre) island in Old River
McDonald Island			San Joaquin	2,400-hectare (5,900-acre) island, bounded by San Joaquin River, Middle River, Latham Slough, and Empire Cut.
Merritt Island			Yolo	A 5,000 acres (2,000 ha) island formed by the Sacramento River to the southeast and Elk Slough to the west, located directly across the Sacramento from Hood.
Ryer Island			Solano	4,750-hectare (11,700-acre), bounded by Miner Slough and Steamboat Slough.
Sherman Island			Sacramento	5,500-hectare (14,000-acre) island bounded by the Sacramento River, Three Mile Slough, and the San Joaquin River.
Staten Island			San Joaquin	3,700-hectare (9,100-acre) island bounded and flanked by the North Mokelumne River and South Mokelumne River.
Sutter Island			Sacramento	Formed by Sacramento River to the northeast, Steamboat Slough to the southeast, and Sutter Slough to the west. Located across the Sacramento River from Paintersville.
Twitchell Island			Sacramento	3,000-hectare (7,400-acre), bounded by Seven Mile Slough, San Joaquin River, and Three Mile Slough
Venice Island			San Joaquin	1,250-hectare (3,100-acre) island bounded by Potato Slough, Little Connection Slough, Stockton Deepwater Channel Venice Cut, and San Joaquin River.
Victoria Island			San Joaquin	2,900-hectare (7,200-acre) island bounded by North Victoria Canal, Middle River, Victoria Canal, and Old River.
West Island			Sacramento
Winter Island			Contra Costa
Woodward Island			San Joaquin	725-hectare (1,790-acre) island bounded by Bacon Island, Old River, Middle River, and Woodward Canal

Channel Islands

The Channel Islands are a group of eight main islands and several minor islands in the Pacific Ocean off the coast of Santa Barbara, Los Angeles, and Ventura counties in Southern California. The four northern islands are protected in Channel Islands National Park, while two are used by the U.S. Navy. These Islands are part of the Greater Los Angeles Area.

Island	Image	Coordinates	Description
Anacapa Island			Located 14 miles (23 km) off the coast of Ventura, California. It contains 728 acres (295 ha) of land spread across three mountainous islets. The island has only three permanent residents. Part of the Greater Los Angeles Area.
Begg Rock			A 15-foot (4.6 m) high rock, located 8 miles (13 km) from San Nicolas Island.
Prince Island			Located near San Miguel Island and measures about 35 acres (14 ha).
San Clemente Island			Southernmost Channel Island, containing 56.81 square miles (147.1 km2) of land. It is 24 miles (39 km) long, and uninhabited. An active U.S. Navy base is located on the island. In Los Angeles County.
San Miguel Island			Westernmost Channel Island, measuring 8 miles (13 km) long, 3.7 miles (6.0 km) wide, and containing 9,325 acres (3,774 ha) of land. The island is uninhabited, and is rarely visited. Part of the Greater Los Angeles Area.
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 (5,893 ha). Part of the Greater Los Angeles Area.
Santa Barbara Island			Smallest Channel Island at 640 acres (260 ha) in area; it is located roughly between San Nicolas and Santa Catalina Islands. Part of the Greater Los Angeles Area.
Santa Catalina Island			The most populous of the Channel Islands, with 3,696 residents as of 2000. It is about 22 miles (35 km) long with a maximum width of 8 miles (13 km). It covers 74.98 square miles (194.2 km2). In Los Angeles County.
Santa Cruz Island			Santa Cruz Island measures 22 miles (35 km) long with an average width of 4 miles (6.4 km), covering 96.5 square miles (250 km2). 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. Part of the Greater Los Angeles Area.
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 (42 km) off the coast of Santa Barbara, California. Part of the Greater Los Angeles area.
Shag Rock			Small islet located off the north shore of Santa Barbara Island, and is only about 1 acre (0.40 ha).
Sutil Island			Located off the southwest shore of Santa Barbara Island, and is about 12 acres (4.9 ha). It is named for a Spanish ship exploring the West Coast in an expedition led by Sebastián Vizcaíno.

Greater Los Angeles Area

The Greater Los Angeles Area is an urban area on the Pacific coast of southern California.

Island	Image	Coordinates	Description
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			A former island in Los Angeles Harbor, removed in 1928 and sometimes referred to as Isla Del Umberto or 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.
Naples Islands			A neighborhood in Long Beach that consists of three different islands divided by canals which empty out into Alamitos Bay.
Terminal Island			An artificial island shared between the cities of Los Angeles and Long Beach. It is 3.5 miles (5.6 km) long and covers an area of 4.46 square miles (11.6 km2).
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.

Newport Bay

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

Island	Image	Coordinates	Description
Balboa Island			A 50-hectare (120-acre), densely populated harbor island with 1,500 expensive homes. Partially created as a result of the Santa Ana River flooding in 1824, then artificially expanded to its present size.
Bay Island			West of Balboa Island.
Harbor Island
Lido Isle			Northwest of Balboa Island.
Linda Isle			North of Harbor Island.

Lake islands

Island	Image	Coordinates	Lake	Description
Beaver Island			Shasta Lake	An island in the Pit River Arm of the lake, located just west of the Pit River Bridge and Bridge Bay Resort/marina.
Fannette Island			Lake Tahoe	The only major island in Lake Tahoe, located within Emerald Bay.
Main Island			Lake Casitas	A 1.5 miles (2.4 km) long, 850-foot (260 m) high island rising 512 feet (156 m) 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 (4.0 km) long and 2 miles (3.2 km) wide, and is the largest Mono Lake island.
Rattlesnake Island			Clear Lake	A 53-acre (21 ha) 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.
Ridgeville Islands			Trinity Lake	A group of forested islets in the Stewart Fork arm about 4 mi (6.4 km) northwest of Trinity Dam.
Ski Island			Shasta Lake	An island in the Pit River arm of the lake, located shortly north of Bear Mountain.
Slaughterhouse Island			Shasta Lake	An island in the Sacramento River Arm of the lake, located about 3 mi (4.8 km) northeast of Shasta Dam.

River islands

Island	Image	Coordinates	River	Description
Cannibal Island			Eel River	An island in the estuary of the Eel River, bounded by the Eel River, Mosley Slough and Sevenmile Slough.
Circle Island			San Joaquin River	An island formed by side channels of the San Joaquin River in the San Luis National Wildlife Refuge near Los Banos.
Cobbs Island			San Joaquin River	An island at mile 259 of the San Joaquin River north of Fresno, contiguous with nearby Island No. 1.
Cock Robin Island			Eel River	An island in the estuary of the Eel River, west of Loleta, between Eel River and Ropers Slough.
Deer Island			Colorado River	An island at mile 169 of the Colorado River on the California–Arizona border, near Parker, Arizona.
Foster Island			Sacramento River	An island at mile 211 of the Sacramento River near Merrills Landing.
Golden State Island			Sacramento River	An island at mile 190 of the Sacramento River between Sacramento River and Murphy Slough, directly across from Phelan Island.
Hall Island			Colorado River	An island at mile 145 of the Colorado River, west of the California–Arizona border.
Hanson Island			Sacramento River	An island at mile 171 of the Sacramento River, near Codora, between Sacramento River and Beehive Bend.
Happy Isles			Merced River	A group of small islands in the Merced River at the upper end of Yosemite Valley, in Yosemite National Park.
Hartley Island			Sacramento River	An island at mile 174 of the Sacramento River near Glenn.
Horse Island			Colorado River	An island at mile 144 of the Colorado River, west of the California–Arizona border.
Ledger Island			San Joaquin River	An island at mile 264 of the San Joaquin River north of Fresno, shortly below Friant Dam.
Lower Foster Island			Sacramento River	An island at mile 210 of the Sacramento River near Merrills Landing, immediately south of Foster Island.
Mooney Island			Sacramento River	An island at mile 236 of the Sacramento River north of Gerber.
Mosley Island			Eel River	The westernmost and smallest named island in the Eel River estuary, bounded by Eel River, North Bay and Mosley Slough.
Packer Island			Sacramento River	An island at mile 167 of the Sacramento River near Codora, between Sacramento River and Packer Lake (oxbow lake in seasonal channel).
Phelan Island			Sacramento River	An island at mile 189 of the Sacramento River near Rotavele, between the Sacramento River and Negro Sam Slough, directly across from Golden State Island.
Ryan Island			Sacramento River	An island at mile 184 of the Sacramento River near Ordbend.
Scout Island			San Joaquin River	A seasonal island in the San Joaquin River in north Fresno.
Snaden Island			Sacramento River	An island at mile 207 of the Sacramento River near Capay, between the Sacramento River and Snaden Slough.
Todd Island			Sacramento River	An island at mile 237.5 of the Sacramento River near Dairyville.
Turner Island			San Joaquin River	A large island along the San Joaquin River and Mariposa Slough near Los Banos, in Merced National Wildlife Refuge.

Miscellaneous

Island	Image	Coordinates	Description
Rincon Island			A 1 acre (0.40 ha) artificial island off the coast of Ventura County, leased for oil and gas production.

See also

• Geography of California
• List of coastal islands of the Californias
• List of islands of the United States
• Outline of California

External links

• California Department of Water Resources.ca.gov: Delta Waterways