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The Department of Defense is America's largest government agency. With our military tracing its roots back to pre-Revolutionary times, the department has grown and evolved with our nation. Our mission is to provide the military forces needed to deter war and ensure our nation's security.

$740.5 Billion

National Defense Budget

2.91 Million

Service Members & Civilians

4,800 Sites

In Over 160 Countries

Armed Forces

The Army, Marine Corps, Navy, Air Force, Space Force and Coast Guard are the armed forces of the United States. The Army National Guard and the Air National Guard are reserve components of their services and operate in part under state authority.

Combatant Commands

The Defense Department has 11 combatant commands, each with a geographic or functional mission that provides command and control of military forces in peace and war.

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Office of the Secretary of Defense

Top civilian defense decision-makers work with the secretary to develop policy, operational and fiscal plans, manage resources and evaluate programs.

Secretary Priorities

The Department of Defense is focused on the following areas:

The guided missile destroyer USS Chafee launches a Block V Tomahawk missile during an exercise in the Pacific Ocean, Dec. 1, 2020.

Defend the Nation

A U.S. soldier participates in a class on indirect fire with Thai counterparts in Nakhon Ratchasima, Thailand, Feb. 26, 2020, during Hanuman Guardian 20, an exercise to demonstrate commitment to the U.S.-Thailand alliance.

Succeed Through Teamwork

Air Force Lt. Col. Paul Lopez, second from left, commander of the Air Combat Command F-22 Demonstration Team, officiates a reenlistment ceremony for Staff Sgt. Annemarie Prozzillo, an aircrew flight equipment technician for the team, at the Dubai Airshow in the United Arab Emirates, Nov. 18, 2019.

Take Care of Our People


The Department of Defense is America's oldest and largest government agency, tracing its roots back to pre-Revolutionary times. Learn about DOD’s rich history and innovations.

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The Pentagon, with its iconic design, is the headquarters of the Department of Defense. Find out more about DOD’s mission and organization.

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Press & Media

Covering the defense beat and the Pentagon? Here's what you need to know.

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