A large, rare example of a 48 star American 'Union Jack' naval flag, cotton construction 50 x 36 in., depicting the canton of the U.S. Flag at the time, 48 stars on blue background. Two metal grommets are sewn onto the canvas white left margin, along with the stamp 'Union Jack No 7 Mare Island Dec. 1943.' This flag was used by the United States Navy from 1912-1959, across both World Wars, the period between the admission to the Union of Arizona and Alaska. Slightly worn, expected from age, else very fine. Mare Island California was the site of U.S. Navy shipyard active until 1993. During World War II the yard employed almost 50,000 workers, built 21 new vessels and repaired countless others for the Pacific Fleet.