Structure of the United States Army

From Infogalactic: the planetary knowledge core
Jump to: navigation, search

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


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 governor of their state 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. The last time an approximation of this occurred was during the American Civil War when the Confederate States of America activated the "Home Guard" in 1865, drafting all males, regardless of age or health, into the Confederate Army.

During the First World War, the "National Army" was organized to fight the conflict.[1] 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.[2]

In 1941, the "Army of the United States" was founded to fight the Second World War. The Regular Army, Army of the United States, the National Guard, and Officer/Enlisted Reserve Corps (ORC and ERC) existed simultaneously.[citation needed]

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.[2][dead link]

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 or Unit Training Assemblies (UTAs), and conduct 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 state's governors. However, units of the National Guard can be federalized by presidential order and against the governor's wishes.[3]

Administrative and Operational


Headquarters Department of the Army (HQ DA) Staff

Chart summarizing the organization of the Department of the Army's Headquarters as of 2010.

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 U.S. Army Chief of Staff. The U.S. Army Chief of Staff is a member of the Joint Chiefs of Staff, a body composed of the service chiefs from each service who advise the President 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 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).[5] IG teams might then be assigned to a case, if need be, to perform inspections, assessments, and investigations.[6]

Operational and Tactical

Levels of Command

Army Commands
Map showing the six geographical commands of the U.S. Army.

There are six geographical Unified Combatant Commands (COCOMs).

Each command will eventually have a numbered army as operational command, except in the case of U.S. Army Pacific, which will not maintain one but will have a numbered army for U.S. Army forces in the Republic of Korea.

Army Cyber Command is a component of United States Cyber Command, which itself is a component of United States Strategic Command. The commander of Army Cyber is also commander of Second Army. Second Army is now a direct reporting unit to the Army CIO/G-6, with CIO reporting to the Secretary of the Army, while G-6 reports to the Army Chief of Staff. Army Network Enterprise Technology Command/9th Army Signal Command (NETCOM/9thSC(A)), formerly reporting directly to the CIO/G-6, is now a component of Second Army.

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. The Air Force provides air transport, and Surface Deployment and Distribution Command provides ocean transport.

Army Commands[11] Current Commander Location of Headquarters
United States Army Forces Command (FORSCOM) GEN Daniel B. Allyn Fort Bragg, North Carolina
United States Army Training and Doctrine Command (TRADOC) GEN David G. Perkins Fort Eustis, Virginia
United States Army Materiel Command (AMC) GEN Dennis L. Via Redstone Arsenal, Alabama
Army Service Component Commands Current Commander Location of Headquarters
United States Army Central (USARCENT) U.S. Third Army LTG James L. Terry[12] Shaw Air Force Base, South Carolina
United States Army North (USARNORTH) U.S. Fifth Army LTG Perry L. Wiggns[13] Fort Sam Houston, San Antonio, Texas
United States Army South (USARSO) U.S. Sixth Army MG Simeon Trombitas Fort Sam Houston, Texas
United States Army Europe (USAREUR) U.S. Seventh Army LTG Donald M. Campbell, Jr. Lucius D. Clay Kaserne, Wiesbaden, Germany
United States Army Africa (USARAF) MG David R. Hogg, USA[14] Caserma Ederle, Vicenza, Italy
United States Army Pacific (USARPAC) GEN Vincent K. Brooks [15] Fort Shafter, Hawaii
Eighth United States Army (EUSA) LTG Joseph F. Fil, Jr. Yongsan Army Garrison, Seoul
United States Army Special Operations Command (USASOC) LTG Charles Cleveland Fort Bragg, North Carolina
Surface Deployment and Distribution Command (SDDC) BG James L. Hodge[16] Fort Eustis, Virginia
United States Army Space and Missile Defense Command/United States Army Strategic (USASMDC/ARSTRAT) LTG Richard P. Formica Redstone Arsenal, Alabama
United States Army Cyber Command (USARCYBER) LTG Edward C. Cardon National Capital Region
Direct Reporting Units Current Commander Location of Headquarters
Second United States Army LTG Edward C. Cardon National Capital Region
United States Army Medical Command (MEDCOM) LTG Nadja West Fort Sam Houston, Texas
United States Army Intelligence and Security Command (INSCOM) MG George J. Franz III Fort Belvoir, Virginia
United States Army Criminal Investigation Command (USACIDC) BG Rodney L. Johnson Fort Belvoir, Virginia
United States Army Corps of Engineers (USACE) LTG Thomas P.Bostick Washington, D.C.
United States Army Military District of Washington (MDW) MG Michael Sr. Linnington Fort McNair, Washington, D.C.
United States Army Test & Evaluation Command (ATEC) MG Roger A. Nadeau Alexandria, Virginia
United States Military Academy (USMA) LTG Robert L. Caslen West Point, New York
United States Army Reserve Command (USARC) LTG Jeffrey W. Talley Fort Bragg, North Carolina
United States Army Acquisition Support Center (USAASC) Mr. Craig A. Spisak Fort Belvoir, Virginia
United States Army Installation Management Command (IMCOM) LTG Robert Wilson Arlington, Virginia

Regular Army Divisions

ARNG Divisions

Separate brigades/regiments

US Army Combat Brigades after the current round of deactivations / re-organizations: 32

  • 10 Heavy Brigade Combat Teams
  • 8 Stryker Brigade Combat Teams
  • 6 Infantry Brigade Combat Teams (light)
  • 5 Infantry Brigade Combat Teams (airborne)
  • 3 Infantry Brigade Combat Teams (air assault)
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 (100–442 Inf (USAR), 3-172 Inf (Mtn) (Vermont Army National Guard) etc.).

Tactical organization

Most U.S. Army units can be operationally divided into the following components from largest to smallest:

  • Field army: Now primarily an administrative arrangement, consisting of multiple corps. The last time a multiple-corps army took the field was Third Army directing VII and XVIII Corps during Operation Desert Storm. Armies now also operate as Army Service Component Commands (ASCCs) of unified combatant commands, such as Seventh Army/USAREUR. Armies have also effectively operated as military districts formerly in the continental United States. Fifth Army and First Army performed this function up until recently. Usually commanded by a General.
  • Corps: Formerly consisting of two or more divisions and organic support brigades, they are now termed an "operational unit of employment", that may command a flexible number of modular units. Usually commanded by a Lieutenant General. 20,000–45,000 soldiers.
  • Division: Formerly consisted of three maneuver brigades, an artillery brigade, a division support command, an aviation brigade, an engineer brigade (in heavy divisions only) and other support assets. Until the Brigade Combat Team program was developed, the division was the smallest self-sufficient level of organization in the U.S. Army. Current divisions are "tactical units of employment", and may command a flexible number of modular units, but generally will include three brigade combat teams and a combat aviation brigade, supported by a staff in a Headquarters and Headquarters Battalion. Usually commanded by a Major General. 10,000–15,000 soldiers.
  • Brigade (or group): Composed of two or more battalions, with a Brigadier General or a Colonel as commander, supported by a staff in a Headquarters and Headquarters Company. Maneuver brigades have transformed into Brigade combat teams, generally consisting of three maneuver battalions, a cavalry squadron, a fires battalion, a special troops battalion (with engineers, signals, and military intelligence), and a support battalion. Stryker Brigade Combat Teams have a somewhat larger structure. 3,000–5,000 soldiers.
  • Regiment: The Army, for the most part is no longer organized by Regiments. Rather, Battalions and Squadrons maintain Regimental Affiliations in that they are called (for example), 1st Battalion, 8th Infantry (Regiment is implied) and is written 1–8 Inf. In this case, there is no Regimental Commander and the Battalion is organized as part of a Brigade for combat. The exceptions are those units, such as Armored Cavalry Regiments which remain organized, and fight, as a Regiment and have a Regimental Commander. The written designation is easy to distinguish and commonly misused. A "/" separates levels of command. 1st Squadron, 3rd Armored Cavalry Regiment is written 1/3 ACR whereas the 1st Battalion, 6th Field Artillery (again, Regiment is implied) is written 1–6 FA.
  • Battalion (or Cavalry Squadron): Normally composed of two to five (occasionally as many as eight) companies, troops or batteries and led by a Battalion/Squadron Commander, usually a Lieutenant Colonel supported by a staff in a Headquarters and Headquarters Company/Battery. 300–1,000 soldiers.
  • Company (or artillery battery/cavalry troop): Designated A to C (plus HQ or support companies/batteries/troops) when in a 3 company/battery battalion or A to D when organized in a 4 company/battery battalion. Regimental Troops are designated A to T, depending on the number of Troops. The Troops are then divided into their like Squadrons. Each company/battery/troop is composed of three to four platoons and led by a Company/Battery/Troop Commander, usually a Captain supported by a First Sergeant. 62–190 soldiers.
  • Platoon: Composed of two or more squads and led by a Platoon Leader, usually a First or Second Lieutenant supported by a platoon sergeant (Sergeant First Class). 20–50 soldiers.
  • Section: Usually directed by a Staff Sergeant who supplies guidance for junior NCO Squad leaders. Often used in conjunction with platoons at the company level.
  • Squad: Composed of two teams and is typically led by a Staff Sergeant. 9–10 soldiers.
  • Team: The smallest unit. A fireteam consists of a team leader (usually a Sergeant, but may be as low as a PFC in rare cases), a rifleman, a grenadier, and an automatic rifleman. A sniper team consists of a sniper who engages the enemy and a spotter who assists in targeting and team defense and security. 2–4 soldiers.

Branches and Functional Areas

Personnel in the Army work in various branches, which is their area of training or expertise.

Basic branches - contain groupings of military occupational specialties (MOS) in various functional categories, groups, and areas of the army in which officers are commissioned or appointed (in the case of warrant officers) and indicate an officer’s broad specialty area. (For example, Infantry, Signal Corps, and Adjutant General’s Corps.) Generally, officers are assigned to sequential positions of increasing responsibility and authority within one of the three functional categories of the army branches (Maneuver, Fires and Effects; Operations Support; Force Sustainment) 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 (MOS) 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 (i.e., theology, law, or medicine), or other associated health care areas (e.g., dentistry, veterinary medicine, pharmacy, registered nurse, physician’s assistant). 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 (AMEDD) 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 (with permission from the Judge Advocate General) 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.[17]

Basic branches and date established[18]
Special branches and date established[18]
  • Army Medical Department, 27 July 1775
  • Medical Corps, 27 July 1775
  • Chaplain Corps, 29 July 1775
  • Judge Advocate General's Corps, 29 July 1775
  • Army Nurse Corps, 2 February 1901
  • Dental Corps, 3 March 1911
  • Veterinary Corps, 3 June 1916
  • Medical Service Corps, 30 June 1917
  • Army Medical Specialist Corps, 16 April 1947

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:

Maneuver, Fires and Effects (MFE) Branches and Functional Areas


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.

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.

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 (light planes and rotary wing aircraft) 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 (part of the U.S. Army Coast Artillery Corps) 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. Subsequently redesignated the Civil Affairs Branch on 2 October 1955, 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.


  • Public Affairs
  • Information Operations

Operations Support (OS) Branches and Functional Areas

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."

  • Cyber approved Sep 2014, previously Information Systems Management
  • Telecommunication Systems Engineer
  • Space Operations

Intelligence, Surveillance, and Reconnaissance (ISR) & Area Expertise

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.

  • Strategic Intelligence
  • Foreign Area Officer (FAO)

Plans development

  • Strategic Plans and Policy
  • Nuclear and Counterproliferation

Forces development

  • Force Management
  • Operations Research/Systems Analysis (ORSA)
  • Simulation Operations

Education and Training

  • Permanent Academy Professor

Force Sustainment (FS) Branches and Functional Areas

Integrated Logistics Corps

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.[20]

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 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.

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

  • Acquisition Corps

Health Services (HS)

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:

Special 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.[21] 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.

See also


  1. See the Continental Staff System for an explanation of "letter-number" (e.g. G-8) designations.


  1. Archived from the original on 30 August 2009. Retrieved 28 June 2009. Missing or empty |title= (help)<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. 2.0 2.1 Army Reserve Marks First 100 Years : Land Forces : Defense News Air Force
  3. Perpich v. Department of Defense, 496 U.S. 334 (1990)
  4. DCS G2, HQDA
  5. Major Commands
  6. Mission: missing remainder of citation
  7. US Third Army Website
  8. "SETAF Takes on a new mission" (Press release). United States Army. 10 Dec 2008.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  9. "SETAF assumes new mission as Army AFRICOM component" (Press release). United States Army. 13 Jan 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  10. "U.S. Army Africa official mission statement". 2 Nov 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  11. Organization, United States Army
  12. "USARCENT". Retrieved 8 October 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  13. "Army North Leadership". Retrieved 8 October 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  14. Major General David R. Hogg, Commander, U.S. Army Africa . Retrieved 26 June 2010.
  15. "USARPAC Leaders". Retrieved 8 October 2015.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  16. "Commanding General". United States Army, Surface Deployment and Distribution Command. 30 June 2008. Archived from the original on 8 February 2007. Retrieved 4 July 2008.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  18. 18.0 18.1 18.2 "Army Birthdays". United States Army Center of Military History. 31 July 2009. Retrieved 1 June 2010.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  19. Jannie Zaaiman; Louise Leenan (24 February 2015). Iccws 2015 - The Proceedings of the 10th International Conference on Cyber Warfare and Security: ICCWS2015. Academic Conferences Limited. pp. 123–124. ISBN 978-1-910309-96-4.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  20. "Transportation School at Fort Lee prepares for first students | Article | The United States Army". 2010-09-17. Retrieved 2013-07-10.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>