Davis–Monthan Air Force Base (DM AFB) (IATA: DMA, ICAO: KDMA, FAA LID: DMA) is a United States Air Force base 5 miles (4 nmi; 8 km) southeast of downtown Tucson, Arizona. It was established in 1925 as Davis–Monthan Landing Field. The host unit for Davis–Monthan AFB is the 355th Wing (355 WG) assigned to Twelfth Air Force (12AF), part of Air Combat Command (ACC). The base is best known as the location of the Air Force Materiel Command's 309th Aerospace Maintenance and Regeneration Group (309 AMARG), the aircraft boneyard for all excess military and U.S. government aircraft and aerospace vehicles.

Davis–Monthan Air Force Base is a key ACC installation. The 355th Wing (355 WG) provides A-10 Thunderbolt II close air support and OA-10 forward air controllers to ground forces worldwide. The 355 WG is the host unit, providing medical, logistical, mission and operational support to assigned units. The 355 WG is the sole formal training unit for the A-10 aircraft, providing initial and recurrent training to all U.S. Air Force A-10 and OA-10 pilots, to include those in the Air Force Reserve Command (AFRC) and the Air National Guard (ANG). The 355th is ACC's executive agent for INF and START treaty compliance. In October 2018, the 563rd Rescue Group, previously a geographically separated unit of the 23rd Wing at Moody AFB, Georgia, was transferred to the 355th Wing, along with its HC-130J COMBAT KING II and HH-60G Pave Hawk aircraft.

One of the wing's tenant units, the 55th Electronic Combat Group (55 ECG), is a geographically separated unit (GSU) of the 55th Wing (55 WG) at Offutt AFB, Nebraska. Tasked to provide offensive counter-information and electronic attack capabilities in support of U.S. and Coalition tactical air, surface, and special operations forces, the 55 ECG unit employs its Lockheed EC-130H Compass Call aircraft worldwide in tactical air operations in war and other contingencies. It also provides initial and recurrent training to all EC-130H Compass Call pilots, navigators, electronic warfare officers, and aircrew.

Two other major tenant units are assigned to the Air Force Reserve Command (AFRC). The 943rd Rescue Group (structured as a GSU under AFRC's 920th Rescue Wing at Patrick Space Force Base is equipped with HH-60G Pave Hawk helicopters and Guardian Angel personnel. The 943 RQG is tasked to provide combat search and rescue (CSAR) and personnel recovery (PR) support worldwide.

Perhaps the most prominent tenant is the 309th Aerospace Maintenance and Regeneration Group (309 AMARG) of the Air Force Materiel Command (AFMC). As the main location for the 309 AMARG, Davis–Monthan AFB is the sole aircraft boneyard for excess military and U.S. government aircraft and other aerospace vehicles such as ballistic missiles. Tucson's dry climate and alkali soil make it an ideal location to store and preserve aircraft; more than 4,000 military aircraft are parked on the base.

The base was named in honor of World War I pilots Lieutenants Samuel H. Davis (1896–1921) and Chief Engineer Oscar Monthan (1885–1924), both Tucson natives. Monthan enlisted in the Army as a private in 1917, was commissioned as a ground officer in 1918, and later became a pilot; he was killed in the crash of a Martin B2 bomber in Hawaii on March 27, 1924.

First Lieutenant Samuel Howard Davis (November 20, 1896 – December 28, 1921) was a pilot and United States Army Air Service officer. Born to Sam and Effie Davis in 1896 in Dyer County, Tennessee, Davis was known by his middle name, Howard. He attended public schools in Tucson. As a young man, his hobbies included horseback riding and shooting; he was a good marksman.

Davis enrolled at Texas A&M College in 1915 as a student of mechanical engineering, having previously attended the University of Arizona in Tucson. After enlisting in the military in 1917, he was briefly assigned to Fort Hauchuca in Arizona before being transferred to College Station, Texas, to complete his academic studies. He returned to the military after graduation in 1918, assembling airplanes at Kelly Field in San Antonio, Texas. He trained pilots during the first World War, including some pilots who took down German planes. He reached the rank of Second Lieutenant. Davis was honorably discharged from the military about 1919 with the rank of First Lieutenant in the reserve corps. For a time he worked commercial aviation as a manager with the Arizona Aviation Company, where he piloted Orioles and standard manufacture airplanes. Davis married Marjorie Cameron of San Antonio in 1920.