The structure of the United States Army is complex, and can be interpreted in several different ways: active/reserve, operational/administrative, and branches/functional areas.
From time to time the Department of the Army issues Department of the Army General Orders. In addition to base closures, unit citations, certain awards such as the Medal of Honor and Legion of Merit, they may concern the creation of JROTC units and structural changes to the Army. These are listed by year on the Army Publishing Directorate's website.
History
Prior to 1903, members of the National Guard were considered state soldiers unless federalized by the President. Since the Militia Act of 1903, all National Guard soldiers have held dual status: as National Guardsmen under the authority of the governors of their states and as a reserve of the U.S. Army under the authority of the President. Since the adoption of the total force policy, in the aftermath of the Vietnam War, reserve component soldiers have taken a more active role in U.S. military operations. Reserve and Guard units took part in the Gulf War, peacekeeping in Kosovo, and the 2003 invasion of Iraq.
Although the present-day Army exists as an all-volunteer force, augmented by Reserve and National Guard forces, measures exist for emergency expansion in the event of a catastrophic occurrence, such as a large scale attack against the U.S. or the outbreak of a major global war.
The final stage of Army mobilization, known as "activation of the unorganized militia" would effectively place all able-bodied males in the service of the U.S. Army.
During World War I, the National Army was organized to fight the conflict. It was demobilized at the end of World War I.
After World War I, former units were replaced by the Regular Army, the Organized Reserve Corps, and the State Militias. In the 1920s and 1930s, the "career" soldiers were known as the "Regular Army" with the Enlisted Reserve Corps and Officer Reserve Corps augmented to fill vacancies when needed.
In 1941, the Army of the United States was founded to fight World War II. The Regular Army, Army of the United States, the National Guard, and Officer/Enlisted Reserve Corps (ORC and ERC) existed simultaneously.
Post World War II After World War II, the ORC and ERC were combined into the United States Army Reserve. The Army of the United States was re-established for the Korean War and Vietnam War and was demobilized upon the suspension of the Draft.
Active and reserve components The United States Army is made up of three components: one active—the Regular Army; and two reserve components—the Army National Guard and the Army Reserve. Both reserve components are primarily composed of part-time soldiers who train once a month, known as Battle Assembly, Unit Training Assemblies (UTAs), or simply "drills", while typically conducting two to three weeks of annual training each year. Both the Regular Army and the Army Reserve are organized under Title 10 of the United States Code. The National Guard is organized under Title 32. While the Army National Guard is organized, trained, and equipped as a component of the U.S. Army, individual units are under the command of individual states' governors. However, units of the National Guard can be federalized by presidential order and against the governor's wishes.Perpich v. Department of Defense, 496 U.S. 334 (1990)
Administrative
Headquarters Department of the Army (HQ DA) Staff
The U.S. Army is led by a civilian Secretary of the Army, who reports to the Secretary of Defense, and serves as civilian oversight for the Chief of Staff of the United States Army (CSA). The CSA is assisted by the Vice Chief of Staff of the United States Army. The CSA is a member of the Joint Chiefs of Staff, a body composed of the service chiefs from each service who advise the President of the United States and secretary of defense on military matters under the guidance of the chairman and vice chairman of the Joint Chiefs of Staff.
Field Operating Agencies Assistant Secretary of the Army for Manpower and Reserve Affairs Army Equity and Inclusion Agency Army Review Boards Agency United States Army Manpower Analysis Agency Administrative Assistant to the Secretary of the Army United States Army Headquarters Support Agency Army Auditor General United States Army Audit Agency Chief Information Officer Enterprise Cloud Management Agency United States Army Enterprise Services Agency Chief of Public Affairs Army Public Affairs Center Deputy Chief of Staff for Personnel (G-1) Civilian Training Student Education Detachment Army Enterprise Marketing Office Deputy Chief of Staff for Operations, Plans and Training (G-3/5/7) United States Army Aeronautical Services Agency United States Army Command and Control Support Agency (a staff support agency) United States Army Force Management Support Agency United States Army Nuclear and Countering Weapons of Mass Destruction Agency Deputy Chief of Staff for Logistics (G-4) United States Army Logistics Enterprise Support Agency Deputy Chief of Staff for Programs (G-8) Center for Army Analysis Director of the Army Staff United States Army Combat Readiness Center United States Army Provost Marshal General Defense Forensics and Biometrics Agency The Inspector General of the Army United States Army Inspector General Agency The Judge Advocate General of the Army The Judge Advocate General's Legal Center and School United States Army Legal Services Agency
Office of the Inspector General The Inspector General of the Army (IG) maintains open channels of communication for extraordinary issues which might lie outside the purview of the chain of command; it lists points of contact for the 3 Army Commands (ACOMs), the 11 Army Service Component Commands (ASCCs), and 12 Direct Reporting Units (DRUs). IG teams might then be assigned to a case, if need be, to perform inspections, assessments, and investigations.Mission: missing remainder of citation
Inspector General's Corps
Army Commands, and Army Service Component Commands Army Commands (ACOMs) and Army Service Component Commands (ASCCs) serve different purposes. The ACOMs are: Materiel Command and Transformation and Training Command.
Some of the Army Service Component Commands (ASCCs) are components of the six geographical Unified Combatant Commands (CCMDs). Other ASCCs serve the functional CCMDs.
United States Army Central headquartered at Shaw Air Force Base, South Carolina United States Army North headquartered at Fort Sam Houston, Texas United States Army South headquartered at Fort Sam Houston, Texas United States Army Europe headquartered at Lucius D. Clay Kaserne, Wiesbaden, Germany United States Army Africa headquartered at Caserma Ederle, Vicenza, Italy United States Army Pacific headquartered at Fort Shafter, Hawaii.
Army Cyber Command is a component of United States Cyber Command. The commander of Army Cyber used to serve as commander of Second Army. Up until 2017, Second Army was a direct reporting unit to the Army CIO/G-6, with the CIO reporting to the Secretary of the Army, while the G-6 reports to the Army Chief of Staff. A 2017 reorganization eliminated the need for Second Army's network operations coordinating function, and the headquarters was deactivated on 31 March 2017. Army Network Enterprise Technology Command formerly reporting directly to the CIO/G-6, was a component of Second Army. The numerical designation 9th Army Signal Command has now been removed from NETCOM.
In addition, the Army's Special Operations Command administers its Joint Operations units; Space and Missile Defense Command provides global satellite-related infrastructure, and missile defense for the combatant commands, and for the nation. Surface Deployment and Distribution Command provides transport.
Headquarters, United States Department of the Army (HQDA):
Army CommandsCurrent commanderLocation of headquarters United States Army Transformation and Training Command (T2COM) GEN David M. Hodne Austin, Texas United States Army Materiel Command (AMC) LTG Christopher O. Mohan Redstone Arsenal, AlabamaArmy Service Component CommandsCurrent commanderLocation of headquarters United States Army Western Hemisphere Command (USAWHC) GEN Joseph A. Ryan Fort Bragg, North Carolina United States Army Europe and Africa(USAREUR-AF)/Seventh Army MG Christopher Norrie (acting)Clay Kaserne, Wiesbaden, Germany United States Army Pacific (USARPAC) GEN Ronald P. Clark Fort Shafter, Hawaii United States Army Central (ARCENT)/Third ArmyLTG Kevin C. Leahy Shaw Air Force Base, South Carolina United States Army Cyber Command (ARCYBER) LTG Maria B. Barrett Fort Gordon, Georgia United States Army Space and Missile Defense Command/United States Army Forces Strategic Command (USASMDC/ARSTRAT) LTG Sean Gainey Redstone Arsenal, Alabama United States Army Special Operations Command (USASOC) LTG Lawrence G. Ferguson Fort Bragg, North Carolina United States Army Transportation Command (ARTRANS) MG Lance G. Curtis Scott AFB, IllinoisOperational Force HeadquartersCurrent commanderLocation of headquarters Eighth Army (EUSA) LTG Joseph E. Hilbert Camp Humphreys, South KoreaDirect reporting unitsCurrent commanderLocation of headquarters Arlington National Cemetery and Soldiers' and Airmen's Home National Cemetery Katharine Kelley Arlington County, VirginiaJoint Counter-Small Unmanned Aircraft Systems OfficeRedesignation and Reassignment of the United Staters Army Joint Counter-Small Unmanned Aircraft Systems Office army.mil MG David F. Stewart Arlington County, Virginia Military Postal Service Agency BG Gregory S. Johnson Arlington County, Virginia United States Army Acquisition Support Center (USAASC) Craig A. Spisak Fort Belvoir, Virginia United States Army Audit Agency (USAAA) Bruce B. Miller Alexandria, Virginia United States Army Civilian Human Resources Agency (CHRA)DAGO 2017-03, Designation of the United States Army Civilian Human Resources Agency and Its Subordinate Elements As Direct Reporting Unit , apd.army.mil, dated 4 January 2017, last accessed 13 January 2017 Carol Burton Aberdeen Proving Ground, Maryland United States Army Corps of Engineers (USACE) LTG William H. Graham Jr. Washington, D.C. United States Army Corrections Command (ACC) BG Sarah K. Albrycht Arlington County, Virginia United States Army Criminal Investigation Division (USACID) Gregory D. Ford Quantico, Virginia United States Army Human Resources Command (HRC) MG Hope C. Rampy Fort Knox, Kentucky United States Army Intelligence and Security Command (INSCOM) MG Timothy D. Brown Fort Belvoir, Virginia United States Army Medical Command (MEDCOM) LTG Mary K. Izaguirre Joint Base San Antonio, Texas United States Army Reserve Command (USARC) LTG Robert Harter Fort Bragg, North Carolina United States Army Military District of Washington (MDW) MG Antoinette R. Gant Fort Lesley J. McNair, Washington, D.C. United States Military Academy (USMA) LTG James B. Bartholomees III West Point, New York Source: U.S. Army organization
Operational unit structure
Most U.S. Army units can be operationally divided into the following components from largest to smallest: