(Press Enter). U.S. DepartmentofDefense Home News Spotlights About Legal & Administrative About 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. Army Marine Corps Navy Air Force Space Force Coast Guard National Guard 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. Learn More Leaders Secretary of Defense Lloyd J. Austin III Deputy Secretary of Defense Kathleen H. Hicks Chairman of the Joint Chiefs of Staff Army Gen. Mark A. Milley Vice Chairman of the Joint Chiefs of Staff Air Force Gen. John E. Hyten 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. More Info Biographies Secretary Priorities The Department of Defense is focused on the following areas: Defend the Nation Succeed Through Teamwork Take Care of Our People History 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. Learn More Headquarters The Pentagon, with its iconic design, is the headquarters of the Department of Defense. Find out more about DOD’s mission and organization. Learn More DEFENSE.GOV Home News Spotlights About HELPFUL LINKS Live Events Today in DOD Contracts For the Media Contact RESOURCES DOD Resources Help Center DOD / Military Websites Insignia Agency Financial Report POPULAR Coronavirus: DOD Response DOD Expeditionary Civilian Workforce Artificial Intelligence DOD Space Strategy The Department of Defense provides the military forces needed to deter war and ensure our nation's security. Enter Your Search Terms Subscribe

(Press Enter). U.S. DepartmentofDefense Home News Spotlights About Legal & Administrative Multimedia PHOTOS VIDEOS 43:08 IISS Manama Dialogue 1:07 Okinawa’s Horse Whisperer Secretary of Defense Holds Briefing INTERACTIVE EXPERIENCES Tomb of the Unknown Soldier DEFENSE.GOV Home News Spotlights About HELPFUL LINKS Live Events Today in DOD Contracts For the Media Contact RESOURCES DOD Resources Help Center DOD / Military Websites Insignia Agency Financial Report POPULAR Coronavirus: DOD Response DOD Expeditionary Civilian Workforce Artificial Intelligence DOD Space Strategy The Department of Defense provides the military forces needed to deter war and ensure our nation's security. Enter Your Search Terms Subscribe