The 4731st Air Defense Group is a discontinued United States Air Force organization. Its last assignment was with the 64th Air Division of Air Defense Command (ADC) at Ernest Harmon Air Force Base, Newfoundland, Canada, where it was inactived in 1960. The group was formed in 1957 when ADC assumed responsibility for air defense of Newfoundland from Northeast Air Command and controlled a fighter-interceptor squadron at Harmon and two squadron operating radars at dispersed locations. It was discontinued when Goose Air Defense Sector assumed responsibility for air defense of Newoundland.