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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:

Marines launch practice rockets from a High Mobility Artillery Rocket System during Exercise Arctic Edge at Fort Greely, Alaska, March 2, 2020. The exercise focuses on training, tactics, and procedures for operating in an Arctic environment.

Defend the Nation

Marine Corps Cpl. Josue Batista explains the capabilities of the joint light tactical vehicle to Japanese soldiers at Hokkudaien Training Area, Japan, Jan. 21, 2020, during Northern Viper. The exercise enhances the U.S.-Japan alliance by allowing units to maintain lethality and proficiency in infantry and combined arms tactics.

Succeed Through Teamwork

Air Force Staff Sgt. Jason Dieterle and his family head to the Aviano Elementary School building at Aviano Air Base, Italy, Aug. 24, 2020. It was the first time students were allowed back to the schools since they closed in February due to COVID-19. Parents were given the option to bring their kids to school or continue virtual education from home.

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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