Treasure Island - artificial island created for 1939–40 exposition

Treasure Island was created in 1936–37 with dredged bay material and landfill to serve as the site of the 1939–1940 Golden Gate International Exposition. The man-made island was later used as Naval Station Treasure Island and remains notable as an engineered island in San Francisco Bay. Engineering and environmental reports have documented issues related to engineered fill, including seismic liquefaction susceptibility and soil contamination concerns that have guided redevelopment and remediation efforts.