The 821st Strategic Aerospace Division is an inactive United States Air Force organization. Its last assignment was with Fifteenth Air Force at Ellsworth Air Force Base, South Dakota, where it was inactivated on 30 June 1971. The division was activated as the 821st Air Division at Ellsworth in 1959 to command Boeing B-52 Stratofortress units of Strategic Air Command (SAC), which had been dispersed along the northern border of the United States to reduce their vulnerability to Soviet missile attacks.