Alameda is a city in Alameda County, California, United States. It is located on Alameda Island and Bay Farm Island, and is adjacent to and west of Oakland and in eastern San Francisco Bay across from San Francisco and South San Francisco, in the San Francisco Bay Area. Bay Farm Island, a portion of which is also known as "Harbor Bay Isle", is not actually an island, and is part of the mainland adjacent to the Oakland International Airport. The city consists of the main original section, with the former Naval Air Station Alameda (NAS Alameda) at the west end of Alameda Island, Southshore along the southern side of Alameda Island, and Bay Farm Island, which is part of the mainland proper. The area of the former NAS is now known as "Alameda Point." The Southshore area is separated from the main part of Alameda Island by a lagoon; the north shore of the lagoon is located approximately where the original south shore of the island was. Alameda Point and Southshore are built on bay fill.