Structure of the United States Army


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.
This page aims to portray the current overall structure of the US Army.

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 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, 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.

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. 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

The Inspector General of the Army 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, the 11 Army Service Component Commands, and 12 Direct Reporting Units. IG teams might then be assigned to a case, if need be, to perform inspections, assessments, and investigations.
There are six Army Service Component Commands assigned, one each, to the six geographical Unified Combatant Commands.
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 inactivated on March 31, 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 :
Army CommandsCurrent commanderLocation of headquarters
United States Army Forces Command GEN Michael X. GarrettFort Bragg, North Carolina
United States Army Futures Command GEN John M. MurrayAustin, Texas
United States Army Materiel Command GEN Gustave F. PernaRedstone Arsenal, Alabama
United States Army Training and Doctrine Command GEN Paul E. Funk IIFort Eustis, Virginia
Army Service Component CommandsCurrent commanderLocation of headquarters
United States Army Africa /Ninth Army/United States Army Southern European Task ForceMG Roger L. Cloutier Jr.Caserma Ederle, Vicenza, Italy
United States Army Central /Third ArmyLTG Terry FerrellShaw Air Force Base, South Carolina
United States Army Europe /Seventh Army LTG Christopher CavoliClay Kaserne, Wiesbaden, Germany
United States Army North /Fifth ArmyLTG Laura J. RichardsonJoint Base San Antonio, Texas
United States Army Pacific GEN Paul LaCameraFort Shafter, Hawaii
United States Army South /Sixth ArmyMG Clarence K.K. ChinnJoint Base San Antonio, Texas
Surface Deployment and Distribution Command MG Stephen E. FarmenScott AFB, Illinois
United States Army Cyber Command LTG Stephen G. FogartyFort Belvoir, Virginia
United States Army Space and Missile Defense Command/United States Army Strategic Command LTG Daniel L. KarblerRedstone Arsenal, Alabama
United States Army Special Operations Command LTG Francis M. BeaudetteFort Bragg, North Carolina
Operational Force HeadquartersCurrent commanderLocation of headquarters
Eighth Army LTG Michael A. BillsCamp Humphreys, South Korea
Direct reporting unitsCurrent commanderLocation of headquarters
Arlington National Cemetery and Soldiers' and Airmen's Home National CemeteryKatharine KelleyArlington, Virginia
United States Army Acquisition Support Center Craig A. SpisakFort Belvoir, Virginia
United States Army Civilian Human Resources Agency Barbara P. PantherWashington, D.C.
United States Army Corps of Engineers LTG Todd T. SemoniteWashington, D.C.
United States Army Criminal Investigation Command MG Kevin VereenQuantico, Virginia
United States Army Human Resources Command MG Joseph R. CallowayFort Knox, Kentucky
United States Army Installation Management Command LTG Douglas GabramJoint Base San Antonio, Texas
United States Army Intelligence and Security Command MG Christopher S. BallardFort Belvoir, Virginia
United States Army Medical Command LTG R. Scott DingleJoint Base San Antonio, Texas
United States Army Military District of Washington MG Omar JonesFort Lesley J. McNair, Washington, D.C.
United States Army Recruiting Command MG Frank M. MuthFort Knox, Kentucky
United States Army Test and Evaluation Command MG Joel K. TylerAlexandria, Virginia
United States Army War College MG John S. KemCarlisle, Pennsylvania
United States Military Academy LTG Darryl A. WilliamsWest 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:

Armies

V Corps to be headquartered at Fort Knox, Kentucky will be reactivated in autumn of 2020, making it the fourth US Army Corps.

Divisions

Regular Army Divisions
Army National Guard Divisions
US Army Combat Brigades after the current round of deactivations / re-organizations: 31
For 2020, the Army plans to convert one SBCT to a HBCT, and one IBCT to a SBCT, which would bring the totals to 11 HBCTs, 7 SBCTs, and 13 IBCTs.

Smaller units

Combat formations of the US Army at below brigade level include the United States Army Special Forces groups and several reserve separate battalions, 3-172 Inf .

Branches and functional areas

Personnel in the Army work in various branches, which is their area of training or expertise. Traditionally, the branches were divided into three groups combat arms, combat support, and combat service support. Currently, the Army classifies its branches as maneuver, fires, and effects; operations support; and force sustainment.
Basic branches - contain groupings of military occupational specialties in various functional categories, groups, and areas of the army in which officers are commissioned or appointed and indicate an officer's broad specialty area. Generally, officers are assigned to sequential positions of increasing responsibility and authority within one of the three functional categories of the army branches to develop their leadership and managerial skills to prepare them for higher levels of command. The branches themselves are administrative vice operational command structures that are primarily involved with training, doctrine, and manpower concerns. Each branch has a Branch Chief who is the Head of the Branch and usually serves as the respective branch school commandant or director.
Special branches - contain those groupings of military occupational specialties of the army in which officers are commissioned or appointed after completing advanced training and education and/or receiving professional certification in one of the classic professions, or other associated health care areas. Officers of most special branches are restricted to command of units and activities of their respective department/branch only, regardless of rank or seniority. This means, for example, that Army Medical Department branch officers may only command AMEDD units and activities. Likewise, Chaplains are essentially "officers without command" and are ineligible to command operational units and activities. They do, however, supervise junior ranking chaplains and enlisted chaplain's assistants. As an exception to this general rule, JAG Corps officers are eligible to command and may be assigned to non-legal command positions, although ordinarily, like other Special branch officers, a JAG officer will only lead JAG Corps units and activities during their career.
;Basic branches and date established
;Special branches and date established
;Special assignment "branches" insignia
Each branch of the army has a different branch insignia. Per US Army Pamphlet 600-3, dated 1 February 2010, the three functional categories and associated functional groups for the branches and associated functional areas are:

Operations Division (OD) Branches and Functional Areas

Maneuver

Ten companies of riflemen were authorized by a resolution of the Continental Congress on 14 June 1775. However, the oldest Regular Army infantry regiment, the 3rd Infantry Regiment, was constituted on 3 June 1784, as the First American Regiment.
The Armor Branch traces its origin to the Cavalry.
A regiment of cavalry was authorized to be raised by the Continental Congress Resolve of 12 December 1776. Although mounted units were raised at various times after the Revolution, the first in continuous service was the United States Regiment of Dragoons, organized in 1833. The Tank Service was formed on 5 March 1918. The Armored Force was formed on 10 July 1940. Armor became a permanent branch of the army in 1950.
Following the establishment of the U.S. Air Force as a separate service in 1947, the army began to develop further its own aviation assets in support of ground operations. The Korean War gave this drive impetus, and the war in Vietnam saw its fruition, as army aviation units performed a variety of missions, including reconnaissance, transport, and fire support. After the war in Vietnam, the role of armed helicopters as tank destroyers received new emphasis. In recognition of the growing importance of aviation in army doctrine and operations, aviation became a separate branch on 12 April 1983.
The Continental Congress unanimously elected Henry Knox "Colonel of the Regiment of Artillery" on 17 November 1775. The regiment formally entered service on 1 January 1776.
The Air Defense Artillery branch descended from the Anti-Aircraft Artillery into a separate branch on 20 June 1968.

Maneuver Support

Continental Congress authority for a "Chief Engineer for the Army" dates from 16 June 1775. A corps of engineers for the United States was authorized by the Congress on 11 March 1789. The Corps of Engineers as it is known today came into being on 16 March 1802, when the President was authorized to "organize and establish a Corps of Engineers... that the said Corps... shall be stationed at West Point in the State of New York and shall constitute a Military Academy." A Corps of Topographical Engineers, authorized on 4 July 1838, was merged with the Corps of Engineers in March 1863.
The Chemical Warfare Service was established on 28 June 1918, combining activities that until then had been dispersed among five separate agencies of government. It was made a permanent branch of the Regular Army by the National Defense Act of 1920. In 1945, it was re-designated the Chemical Corps.
A Provost Marshal General's Office and Corps of Military Police were established in 1941. Prior to that time, except during the Civil War and World War I, there was no regularly appointed Provost Marshal General or regularly constituted Military Police Corps, although a "Provost Marshal" can be found as early as January 1776, and a "Provost Corps" as early as 1778.

Special Operations Forces

The first special forces unit in the Army was formed on 11 June 1952, when the 10th Special Forces Group was activated at Fort Bragg, North Carolina. A major expansion of special forces occurred during the 1960s, with a total of eighteen groups organized in the Regular Army, Army Reserve, and Army National Guard. As a result of renewed emphasis on special operations in the 1980s, the Special Forces Branch was established as a basic branch of the army effective 9 April 1987, by General Order No. 35, 19 June 1987. Special forces are part of U.S. special operations forces
Established as a basic branch effective 16 October 2006 per General Order 30, 12 January 2007.
The Civil Affairs/Military Government Branch in the Army Reserve Branch was established as a special branch on 17 August 1955. It was subsequently redesignated the Civil Affairs Branch on 2 October 1955, and it has continued its mission to provide guidance to commanders in a broad spectrum of activities ranging from host–guest relationships to the assumption of executive, legislative, and judicial processes in occupied or liberated areas. Became a basic branch effective 16 October 2006 per General Order 29, on 12 January 2007.

Effects

Network and Space Operations

The Signal Corps was authorized as a separate branch of the army by act of Congress on 3 March 1863. However, the Signal Corps dates its existence from 21 June 1860, when Congress authorized the appointment of one signal officer in the army, and a War Department order carried the following assignment: "Signal Department – Assistant Surgeon Albert J. Myer to be Signal Officer, with the rank of Major, 27 June 1860, to fill an original vacancy."
Intelligence has been an essential element of army operations during war as well as during periods of peace. In the past, requirements were met by personnel from the Army Intelligence and Army Security Reserve branches, two-year obligated tour officers, one-tour levies on the various branches, and Regular Army officers in the specialization programs. To meet the army's increased requirement for national and tactical intelligence, an Intelligence and Security Branch was established effective 1 July 1962, by General Order No. 38, on 3 July 1962. On 1 July 1967, the branch was re-designated as Military Intelligence.

Integrated Logistics Corps

The Quartermaster Corps, originally designated the Quartermaster Department, was established on 16 June 1775. While numerous additions, deletions, and changes of function have occurred, its basic supply and service support functions have continued in existence.
The Ordnance Department was established by act of Congress on 14 May 1812. During the Revolutionary War, ordnance material was under supervision of the Board of War and Ordnance. Numerous shifts in duties and responsibilities have occurred in the Ordnance Corps since colonial times. It acquired its present designation in 1950. Ordnance soldiers and officers provide maintenance and ammunition support.
The history of the Transportation Corps starts with World War I. Prior to that time, transportation operations were chiefly the responsibility of the Quartermaster General. The Transportation Corps, essentially in its present form, was organized on 31 July 1942. The Transportation Corps is headquartered at Fort Lee, Virginia.
Established by General Order 6, 27 November 2007. Consists of multifunctional logistics officers in the rank of captain and above, drawn from the Ordnance, Quartermaster and Transportation Corps.

Soldier Support

The post of Adjutant General was established 16 June 1775, and has been continuously in operation since that time. The Adjutant General's Department, by that name, was established by the act of 3 March 1812, and was re-designated the Adjutant General's Corps in 1950.
The Finance Corps is the successor to the old Pay Department, which was created in June 1775. The Finance Department was created by law on 1 July 1920. It became the Finance Corps in 1950.

Acquisition Corps

The Army Medical Department and the Medical Corps trace their origins to 27 July 1775, when the Continental Congress established the army hospital headed by a "Director General and Chief Physician." Congress provided a medical organization of the army only in time of war or emergency until 1818, which marked the inception of a permanent and continuous Medical Department. The Army Organization Act of 1950 renamed the Medical Department as the Army Medical Service. In June 1968, the Army Medical Service was re-designated the Army Medical Department. The Medical Department has the following branches:
The legal origin of the Chaplain Corps is found in a resolution of the Continental Congress, adopted 29 July 1775, which made provision for the pay of chaplains. The Office of the Chief of Chaplains was created by the National Defense Act of 1920.
The Office of Judge Advocate General of the Army is deemed to have been created on 29 July 1775, the date of appointment of Colonel William Tudor as the first U.S. Army Judge Advocate General. The history of the branch has generally paralleled the origin and development of the American system of military justice. The Judge Advocate General Department, by that name, was established in 1884. Its present designation as a corps was enacted in 1948.