This is a list of military installations owned or used by the United States Armed Forces both in the United States and around the world. This list details only current or recently closed facilities; some defunct facilities are found at Category:Former military installations of the United States.

A military installation is the basic administrative unit into which the U.S. Department of Defense groups its infrastructure, and is statutorily defined as any “base, camp, post, station, yard, center, or other activity under the jurisdiction … [or] operational control of the Secretary of a military department or the Secretary of Defense.” An installation or group of installations may, in turn, serve as a base, which DOD defines as “a locality from which operations are projected or supported.”

The U.S. military maintains hundreds of installations, both inside the United States and overseas (with at least 128 military bases located outside of its national territory as of July 2024). According to the U.S. Army, Camp Humphreys in South Korea is the largest overseas base in terms of area. Most of foreign military installations are located in NATO countries, Middle East countries, South Korea, Australia, Japan.

U.S. officials have been accused of collaborating with oppressive regimes and anti-democratic governments to secure their military bases, from Central America to the Middle East, Africa, and Asia. The Democracy Index classifies many of the forty-five current non-democratic U.S. base hosts as fully "authoritarian governments". Military bases in non-democratic states were often rationalized during the Cold War by the U.S. as a necessary if undesirable condition in defending against the communist threat posed by the Soviet Union. Few of these bases have been abandoned since the end of the Cold War.

Several rounds of closures and mergers have occurred since the end of World War II, a procedure most recently known as Base Realignment and Closure. Anti-racist agitation in the early 2020s led to calls for changing bases to remove the names of Confederate figures who fought against the Union during the American Civil War. The Naming Commission was created by the National Defense Authorization Act for Fiscal Year 2021, and renaming began in December 2022.