Early unknown observed near San Francisco Bay at San Pablo, California (1948)

Project Blue Book Case #208. On September 23, 1948, an unidentified object was observed over San Pablo, California — a community on the northeastern shore of San Francisco Bay. The Bay Area's concentration of military installations — Mare Island Naval Shipyard, Hamilton AFB, NAS Alameda — made it one of the most defense-dense regions on the West Coast. This early Project Sign-era case was classified "Unknown."