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U.S. Army Organization

The U.S. Army is organized by principles that are deeply embedded in history and tradition. The echelons of combat units and support elements are designed with the flexibility to serve in peace and in war.

CPL Harold J. Dunn stands guard at Combat Command A, 9th Armored Div, 3rd U.S. Army, 12th Army Group, quartered in Excelsior Hotel, Coburg, Germany, 24 May 1945.
CPL Harold J. Dunn stands guard at Combat Command A, 9th Armored Div, 3rd U.S. Army, 12th Army Group, quartered in Excelsior Hotel, Coburg, Germany, 24 May 1945.

Today in WW II: 2 Oct 1939 Battle of Kock, the final battle in the invasion of Poland, begins [2-5 October].  More 
2 Oct 1941 Operation Typhoon begins, Germany's all-out offensive against Moscow, leading to Hitler's first important loss.
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U.S. Army Organization

US Army Echelons

The U.S. Army is organized in units of increasing size, from the individual Soldier to multi-corps commands composed of hundreds of thousands of Soldiers with all their support and logistics. The names and composition of Army units vary depending on the role of the unit. That is, there will be differences between the Combat Arms (infantry, armor, artillery, aviation, special forces), Combat Support (intelligence, communications, engineer, military police) and Combat Service Support (supply, maintenance, medical, transportation, chaplain, finance and administration). The unit names and other details have also evolved over time so that today's infantry Division will not be organized the same as a World War II infantry Division.

The nine echelons (levels) of Army units, from smallest to largest, are:

Unit Name Alternative Names Components Commander's Rank
Fireteam   4 Soldiers Staff Sgt
Squad Section (Cavalry) 4-10 Soldiers Sgt or Staff Sgt
Platoon   16-40 Soldiers in 2 or more Squads Lieutenant
Company Troop (Cavalry), Battery (Artillery) 100-200 Soldiers in 3-5 Platoons Captain
Battalion Squadron (Cavalry) 500-900 Soldiers in 4-6 Companies Lt. Colonel
Brigade Group (Logistics or Special Forces) 3,000-5,000 Soldiers in 2-5 Battalions Colonel
Division   10,000 to 18,000 Soldiers in 3 or more Brigades Major General
Corps   2 or more Divisions plus other units organized under the Corps commander Lt. General
Field Army   2 or more Corps plus other units organized under the Field Army commander General (or Lt. General)
Army Group   2 or more Field Armies plus other units organized under the Army Group commander General

In the 1950s, the U.S. Army was reorganized to provide for a more flexible and dispersed formation in the light of atomic-armed forces. Pentomic was basically a divisional reorganization that introduced major changes in all infantry units. The single most important innovation was the elimination of the regiment from the infantry structure, replaced by a new organization called the "battle group." Smaller than a Regiment and larger than a Battalion, the new unit was commanded by a full colonel. Five battle groups were organic to the Pentomic infantry division. Prior to 1957, Battalions were organized into Regiments composed of 3 battalions and a HQ company. Regiments no longer exist as actual units, but are still used as a phantom way of grouping battalions for historical, morale, and other purposes. The battalions are commanded by their brigade headquarters. By June 1958, all fifteen active Regular Army divisions and their subordinate units had been reorganized under these tables, and by mid-1959 all but one of the thirty-seven divisions in the reserve components had adopted the new structure.

All land, sea, and air forces in a geographic area will be termed a Theater, for example the European Theater of Operations in WW II. Since WW II, Field Army and Army Group are not used. Within a Theater, the largest U.S. Army unit is the Army Service Component Command (ASCC) made up of two or more Corps, commanded by a Lt. General or General.

U.S. Army in 2005

Subject to ongoing modernization and transformation, the U.S. Army in the mid-2000s has ten active-duty divisions. Each Division HQ is located as indicated in the table, although a division may have a brigade based at another location.

Division Location
1st Armored Division Germany
1st Cavalry Division Fort Hood, TX
1st Infantry Division (Mechanized) Germany
2d Infantry Division Korea
3d Infantry Division (Mechanized) Fort Stewart, GA
4th Infantry Division (Mechanized) Fort Hood, TX
10th Mountain Division (Light Infantry) Fort Drum, NY
25th Infantry Division (Light) Schofield Barracks, HI
82d Airborne Division Fort Bragg, NC
101st Airborne Division (Air Assault) Fort Campbell, KY

There are four active-duty Corps headquarters:

Corps Location Oversees
V Corps Germany 1st Armored, 1st Infantry Divs
III Corps Fort Hood, TX 1st Cavalry, 4th Infantry Divs
I Corps Fort Lewis, WA 2d & 25th Infantry Divs
XVIII Airborne Corps Fort Bragg, NC 82d & 101st Airborne, 10th Mountain, 3d Infantry Divs

There are five theater-level ASCCs:

ASCC Location Theater Command
U.S. Army Europe (USAREUR) Heidelberg, Germany U.S. European Command
U.S. Army Pacific (USARPAC) Ft Shafter, HI U.S. Pacific Command
U.S. Army South (USARSO) Ft Sam Houston, TX U.S. Southern Command
U.S. Army Central (ARCENT) Ft McPherson, GA Third U.S. Army, the Army component of U.S. Central Command
Eighth U.S. Army (EUSA) Yongsan, Korea Army component of U.S. Forces, Korea.

Major U.S. Army Commands

In addition to the five ASCCs, the Army also includes the MACOMs (major Army commands) for specialized support activities:

MACOM Location Description
Army Corps of Engineers Washington, DC  
Army Criminal Investigation Command Ft Belvoir, VA  
Army Forces Command (FORSCOM) Fort McPherson, GA Trains, mobilizes, deploys, and sustains combat-ready forces for the unified combatant commands
Army Intelligence and Security Command Fort Belvoir, VA  
Army Materiel Command (AMC) Ft Belvoir, VA Provides materiel readiness, including technology, acquisition support, materiel development, logistics power projection, and sustainment
Army Medical Command (MEDCOM) Fort Sam Houston, TX  
Army Military District of Washington Ft McNair, DC Operates Army facilities in the Washington, DC area, including Arlington National Cemetary
Army Space and Missile Defense Command Redstone Arsenal, AL Responsible for ballistic missile defense research, development and deployment
Army Special Operations Command Fort Bragg, NC U.S. Special Operations Command Army component that trains, equips, deploys and sustains Army special-operations forces worldwide
Military Surface Deployment and Distribution Command (SDDC) Scott AFB, IL Provides global surface deployment command and control and distribution operations
Army Training and Doctrine Command (TRADOC) Ft Monroe, VA TRADOC recruits, trains, and educates the Army’s soldiers, develops leaders, supports unit training, develops doctrine, establishes standards, and designs the future Army

Each MACOM includes major subordinate commands (MSCs) and other organizations to focus on and conduct specialized functions.


Following the 9-11 terrorist attacks on the United States, the U.S. Army began its most significant reorganization since World War II, to ensure that the formations of all components are fully manned, equipped, and trained. Units of brigade, division, corps, and the ASCC structure were reviewed with changes expected to take until 2013 to complete.

To modernize the Army while increasing its effectiveness, the number of higher headquarters, brigades and portions of divisions will be reduced to form a greater number of modular Brigade Combat Team (BCT) forces that are expeditionary in nature and deployed continuously in different parts of the world. Each BCT will contain traditional maneuver battalions, along with some Combat Support and Combat Service Support traditionally provided by divisional or corps units.

The Army envisions these types of maneuver BCTs:

  • Armored BCTs: about 3,800 personnel and 1,000 vehicles
  • Infantry BCTs: about 3,000 soldiers
  • Stryker BCTs: about 4,000 personnel
  • Aviation BCTs
  • Sustainment BCTs

Expected strength will be 21 infantry BCTs, 22 armored BCTs, and 5 SBCTs. The Army goal is to have 48 active component BCTs and 32 National Guard BCTs.

Above the BCT level, the command and support organization will be called a "unit of employment x" (UEx). This single level of command will conduct many of the same command and control missions currently being performed by the two levels of command associated with a Division and a Corps. A UEx will be capable of commanding at least six BCTs, including all or part of a Marine Expeditionary Brigade. A different type of unit of employment, the UEy, will serve at a higher level than the UEx and will conduct many of the command and control missions formerly provided by the two levels associated with a corps and an ASCC.

The ongoing transformational changes are meant to ensure that the Army is structured to deploy to remote locations worldwide as part of a joint force. Although providing logistics support to Army forces is especially challenging because of the diversity of equipment and the dispersal of forces, new organizational designs and the introduction of lighter, land vehicles will enable the Army to deploy large forces much more rapidly than in the past and sustain them in noncontiguous environments.

U.S. Army Staff Organization

These definitions apply to the organization of U.S. Army staff, as well as that of the other U.S. military services, as indicated.

Staff (S): A group of officers in the headquarters of a Brigade and Battalion Staff (Army and Marine Corps units smaller than a Brigade or aircraft wings)

General Staff (G): A group of officers in the headquarters of Army or Marine Divisions, Marine Brigades and aircraft wings, or similar or larger units that assist their commanders in planning, coordinating, and supervising operations.

Joint Staff (J): The staff of a commander of a unified or specified command, subordinates unified commands, joint task force, or subordinate functional component (when a functional component command will employ forces from more than one military department), which includes members of several services comprising the force.

Joint Staff is also the staff under the Chairman of the Joint Chiefs of Staff.  The Joint Staff assists the Chairman and, subject to the authority, direction, and control of the Chairman, the other members of the Joint Chief of Staff and Vice Chairman in carrying out their responsibilities.

Naval Staff (N) Naval staffs ordinarily are not organized on these lines, but when they are, they are designated (N-1, N-2, etc…)

  Staff (S) General Staff (G) Joint Staff (J)
1-Personnel S-1 G-1 J-1 (Manpower and Personnel Directorate)
2- Military Intelligence S-2 G-2 J-2
3- Operations S-3 G-3 J-3 (Operations Directorate)
4- Logistics S-4 G-4 J-4 (Logistics Directorate)
5- Civil Affairs/ Military Government   G-5 J-5 (Strategic Plans and Policy Directorate)
6- Command, Control and Communications Directorate     J-6
7- Operational Plans and Interoperability Directorate     J-7
8- Force Structure, Resources, and Assessment Directorate     J-8