San Antonio is home to some of the largest military tenants, likely because of its sheer size and its unique location, which serves as the cultural gateway to the American Southwest. The military installations of San Antonio include:
- Brooks City-Base – As the largest tenant in the United States Air Force, Books City Base also has a strong presence in aerospace medicine. The two, major units of the Brooks City-Base are the United States Air Force School of Aerospace Medicine and the 311th Human Systems Wing.
- Fort Sam Houston – Fort Sam Houston is a support post and medical training facility. It is therefore commonly known as the “Home of the Combat Medic” and the “Home of Army Medicine.” Fort Sam Houston is home to the U.S. Army North, 5th Army Recruiting Brigade, the U.S. Army South, and the 12th ROTC Brigade.
- Kelly Air Field Annex – Once serving as the Kelly Air Force Base, the Kelly Air Field Annex is now the home case for the Texas Air National Guard 149th Fighter Wing and the Air Force Reserve Command’s 433rd Airlift Wing.
- Lackland Air Force Base – Serving the United States Air Force, Lackland Air Force Base is the largest training facility in the United States and is the location of all Basic Military Training for the United States Air Force, the Air Force Reserve and the Air National Guard.
- Randolph Air Force Base – Randolph Air Force Base is home to the Air Education and Technical Command and is where the Air Force conducts pilot training and combat systems officer training. It is also home to the 12th Flying Training Wing, which supports many of the Department of Defense units.