Yerba Buena Island
Yerba Buena Island, 300 acres (121 hectares), W Calif., in San Francisco Bay. It is the midpoint of the San Francisco–Oakland Bay Bridge, which crosses the island through a tunnel. There are coast guard facilities on the island. Neighboring Treasure Island, 400 acres (162 hectares), connected to Yerba Buena by a causeway, was constructed with fill for the Golden Gate International Exposition (1939–40) and was then (1942–97) a U.S. naval air station.