Newark Air Base, Ohio

Though Newark Air Force Base officially closed in 1996, some of the original mission of the base continues under civilian and military management. Around 1,000 people, mostly civilian contractors working for Boeing, repair guidance systems for America's fleet of Intercontinental Ballistic Missiles, and inertial navigation systems for military airplanes. The Air Force's Metrology (calibration and measurement science) facilities on site include a four level calibration laboratory, possibly the largest facility of this type in the world, built underground to be free from minute vibrations. The primary contractor at the site is Boeing's Space and Communication Group, which operates the Guidance Repair Center. Other parts of the old base continue to be developed for commercial tenants.