The 4721st Air Defense Group is a discontinued group of the United States Air Force. Its last assignment was with the 4700th Air Defense Wing at Larson Air Force Base, Washington, where it was last active in1959. The group was formed to provide a single command and support organization for the two fighter interceptor squadrons of Air Defense Command (ADC), that were tenants at Larson, a Tactical Air Command (TAC) base. It was discontinued after the 322d Fighter-Interceptor Squadron moved in 1959, leaving only a single fighter squadron at Larson.