Alameda (island)

Alameda Island

Aerial view of the north end of Alameda Island (left)
Geography
Location	San Francisco Bay, California
Coordinates	37°46′36″N 122°16′40″W / 37.77667°N 122.27778°W / 37.77667; -122.27778Coordinates: 37°46′36″N 122°16′40″W / 37.77667°N 122.27778°W / 37.77667; -122.27778
Coastline	9.25 km (5.748 mi)
Administration
United States
State	California

Alameda Island is an island in the San Francisco Bay in California. It is south and west of, and adjacent to Oakland, and across the bay eastward from San Francisco. Located on the island is most of the city of Alameda, a city in Alameda County. Also located on the island is the Naval Air Station Alameda, a defunct naval air station, as well as a small uninhabited part of San Francisco. The island was originally a peninsula and a part of Oakland, and is now separated from the mainland by the Oakland Estuary. The island is connected to the mainland by four bridges: the Park Street Bridge, Fruitvale Bridge, High Street Bridge, and Bay Farm Island Bridge. The Posey and Webster Street tubes also connect Oakland to Alameda Island.

The island was originally a peninsula 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 tribe. The peninsula became part of the vast Rancho San Antonio granted to Luis Peralta by the viceroyalty under King Ferdinand VII of Spain. The grant was later confirmed by the new Republic of Mexico upon its independence from Spain.