Treasure Island is entirely within the City and County of San Francisco , whose territory extends far into San Francisco Bay and to the tip of the island of Alameda, California .

The island has a raised walkway, circumscribing almost its entire bulk, which is popular for recreation. Sea lions can be observed in the water from the shoreline, and construction of the new eastern span of the San Francisco - Oakland Bay Bridge can be observed from the eastern part of the island.

Treasure Island was built with imported fill on shoals on the north side of Yerba Buena Island for the Expo in 1939. The island sits in the "middle" of the San Francisco - Oakland Bay Bridge . Built by the federal government, Treasure Island was planned for and used as an airport for Pan American Airline's Pacific Rim service of flying boats, of which the China Clipper is an example. After the World's Fair 1939 - 40 exhibition, the island was scheduled to be used as an airport when the Navy offered to exchange Mills Field on the San Francisco Peninsula near the city of Millbrae for the island. The City and County of San Francisco accepted the swap, and the airport was built at Mills Field.

During World War II Treasure Island became part of the Treasure Island Naval Base, and served largely as an electronics and radio communications training school, and as the major Navy departure point for sailors in the Pacific.

In 1996 Treasure Island and the Presidio Army Base were decommissioned and opened to public control, under stipulations. Treasure Island is now part of District 6 of the City and County of San Francisco , though it is still owned by the Navy.

Building One is a Streamline Moderne -styled remnant of the World's Fair and is one of the few buildings remaining from the exposition. Originally intended as the terminal for the airport, it housed the Treasure Island Museum from 1976 to 1997. Today it serves largely as offices for The Villages , a private apartment rental agency. The former housing for officers and their families is rented out to the general public, pending redevelopment and reconstruction of buildings on the island, slated for 2012-2014.

A substantial part of the island is undergoing environmental cleanup by the federal government.

Treasure Island as a Film Location...

In the 1990s and 2000s, Treasure Island's old aircraft hangars served as sound stages used in film and television productions. In 1988, Treasure Island stood in for the Berlin airport in Steven Spielberg 's Indiana Jones and the Last Crusade . Numerous pictures starring Robin Williams were filmed on the island, including Flubber , What Dreams May Come , Patch Adams and Bicentennial Man . Sigourney Weaver 's character in the thriller Copycat lived in an impressive private compound on the island. For three years it served as the site of Comedy Central 's Battlebots television show. The offices and penthouse apartment in Nash Bridges were sets located on the island during the show's production (1996 - 2001). Treasure Island served as the stage location for the " bullet time " visual effect . The island hangars also served as soundstages for the film adaptation of Rent directed by Chris Columbus . It is also used in an establishing shot of The Caine Mutiny, the trial which ostensibly takes place on Treasure Island, though this is never mentioned or referenced in the film.

Future development

In 2005, one of the largest developers of the United States, Lennar Corporation , proposed to build a self-sustaining city on Treasure Island. According to the San Francisco Chronicle , the proposal has 5,500 units of housing in several lowrise buildings, restaurants and a ferry terminal facing San Francisco. The plan also contains several midrise towers, four 40-story towers and one 60-story tower called the Sun Tower (formerly Treasure Island Tower). It also has an organic farm , a wind farm , parkland and tidal marshes . The proposal is designed to be as car-independent as possible, with the ferry terminal and basic goods within a 10-minute walk of the residences. A toll of $5 has been proposed to deter non-residents from driving on to the island. This is a change from the original plan which was more car-dependent and had only one highrise tower. The Navy has signed two "Findings of Suitable Transfer" or FOST documents which allow development plans to continue.

The San Francisco Gaelic Athletic Association has recently leased land on the island to create athletic fields which will be used mainly for Gaelic football and hurling . The 3 fields will be home to future North American Championships as well as visits from Irish All-Star teams.