Alameda Island is an island located in the

San Francisco Bay San Francisco Bay (Chochenyo language, Chochenyo: 'ommu) is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the cities of San Francisco, California, San ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It is south and west of, and adjacent to,

Oakland Oakland is a city in the East Bay region of the San Francisco Bay Area in the U.S. state of California. It is the county seat and most populous city in Alameda County, with a population of 440,646 in 2020. A major West Coast port, Oakland is ...

, and across the bay eastward from

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

. Located on the island is most of the city of Alameda, a city in

Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. A ...

. A very small western tip of the island's territory is technically part of

; however, this is uninhabited and is not separately managed. Alameda Island is the most populated island in the continental

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

that is not located in the

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

metropolitan area. Once located on the island was the Naval Air Station Alameda, a defunct

naval air station A Naval Air Station (NAS) is a military air base, and consists of a permanent land-based operations locations for the military aviation division of the relevant branch of a navy (Naval aviation). These bases are typically populated by squadron ...

. The island was originally a peninsula and a part of Oakland and is now separated from the mainland by the

Oakland Estuary The Oakland Estuary is the strait in the San Francisco Bay Area, California, separating the cities of Oakland, California, Oakland and Alameda, California, Alameda and the Alameda (island), Alameda Island from the East Bay mainland. On its weste ...

. The island is connected to the mainland by six bridges: the Park Street Bridge, the Fruitvale Railroad Bridge, the Miller Sweeney Road Bridge, the High Street Bridge, the Bay Farm Island Bridge, and the Bayfarm Island Bicycle Draw Bridge. The Posey and Webster Street tubes also connect Oakland to Alameda Island.

History

The island was originally a

peninsula A peninsula is a landform that extends from a mainland and is only connected to land on one side. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula. Etymology The word ''peninsula'' derives , . T ...

connected to Oakland. Much of it was low-lying and marshy, but on higher ground, the peninsula and adjacent parts of what is now downtown Oakland were home to one of the largest coastal oak forests in the world. The area was therefore called ''Encinal'', Spanish for "oak grove". ''Alameda'' is Spanish for "grove of poplar trees" or "tree-lined avenue", and was chosen in 1853 by popular vote. The inhabitants at the time of the arrival of the Spanish in the late 18th century were a local band of the

Ohlone The Ohlone ( ), formerly known as Costanoans (from Spanish meaning 'coast dweller'), are a Native Americans in the United States, Native American people of the Northern California coast. When Spanish explorers and missionaries arrived in the l ...

tribe. The peninsula became part of the vast Rancho San Antonio granted to Luis Peralta by the viceroyalty under King

Ferdinand VII of Spain Ferdinand VII (; 14 October 1784 – 29 September 1833) was Monarchy of Spain, King of Spain during the early 19th century. He reigned briefly in 1808 and then again from 1813 to his death in 1833. Before 1813 he was known as ''el Deseado'' (t ...

. The grant was later confirmed by the new Republic of Mexico upon its independence from Spain. Over time, the place became known as Bolsa de Encinal or Encinal de San Antonio. The island was created in 1902 with the opening of a canal on the south side to enhance tidal scouring to keep the estuary to the north cleared for shipping. Landfill was added around the island and stopped once the island had been extended over the San Francisco border. The island contains many Victorian homes built in the late 1800s and early 1900s. Nearly the entire island has been developed. There are several miles of beaches along the south side.

References

{{San Francisco Bay watershed, state=autocollapse *Island Islands of Alameda County, California Islands of Northern California Geography of the San Francisco Bay Area Islands of San Francisco Bay Landforms of the San Francisco Bay Area