Kirtland Air Force Base is surprising for its size and complexity.

At 80 square miles and more than 25,000 employees, Kirtland is one of the largest installations of the U.S. Air Force. It’s also one of the most complex, with three scientific laboratories, two flying organizations, a weapons depot, two headquarters (Air Force safety and systems testing), an astronomical observatory, and the Department of Energy’s biggest field office. The base’s economic impact on Albuquerque totals $4 billion.

Kirtland’s mass and diversity probably spared it in the most recent round of base closures.

Munitions storage has a long history at Kirtland. It started in 1945 with nuclear weapons arriving at Sandia Base (forerunner of the labs) from Los Alamos for practice and loading on modified B-29 bombers. In 1946 the Army began building Site Able in the Manzano foothills and activated the operation in 1950. It became Manzano Base in 1952. The work at Manzano was so secret that servicemen who worked there couldn’t even tell their wives what they did.

Manzano consisted of 122 igloos, or magazines – 81 earth-covered bunkers and 41 tunnels in mountainsides – and four plants scattered through 2,880 acres in the Manzano foothills. In 1952, the Air Force took over Manzano Base and operated the storage depot until it completed a new underground storage complex in 1990. It’s the most modern facility of its kind in the Department of Defense and one of just two nuclear weapons general depots in the United States. The old Manzano storage area, some of which can be seen from Four Hills, was deactivated in 1992.

Today weapons storage is managed by the 377th Air Base Wing, which also functions as Kirtland’s host and landlord to dozens of other organizations at Kirtland.

Kirtland has two major flying outfits: The 58th Special Operations Wing trains 2,000 students a year from all over the world in special operations and combat rescue, helps civilian authorities with local rescues, and supplies people and airlifts during crises. The New Mexico Air National Guard 150th Fighter Wing flies and maintains F-16 Fighting Falcon jet fighters.

Kirtland’s best known tenant is Sandia National Laboratories, a DOE facility with some 8,000 employees, but the base is home to two other labs as well – two directorates of Air Force Research Laboratory. One includes Starfire Optical Range, an astronomical observatory in the Manzano foothills.

Kirtland has not been just another isolated military outpost. The base and its many operations have become an integral part of Albuquerque – so much so that many of its personnel retire here, often returning from other places because they like the city so much. Albuquerque has an estimated 50,000 military retirees.