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.
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:
Sgt or Staff Sgt
16-40 Soldiers in 2 or more Squads
Troop (Cavalry), Battery (Artillery)
100-200 Soldiers in 3-5 Platoons
500-900 Soldiers in 4-6 Companies
Group (Logistics or Special Forces)
3,000-5,000 Soldiers in 2-5 Battalions
10,000 to 18,000 Soldiers in 3 or more Brigades
2 or more Divisions plus other units organized under the Corps commander
2 or more Corps plus other units organized under the Field Army commander
General (or Lt. General)
2 or more Field Armies plus other units organized under the Army Group commander
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.
1st Armored Division
1st Cavalry Division
Fort Hood, TX
1st Infantry Division (Mechanized)
2d Infantry Division
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:
1st Armored, 1st Infantry Divs
Fort Hood, TX
1st Cavalry, 4th Infantry Divs
Fort Lewis, WA
2d & 25th Infantry Divs
XVIII Airborne Corps
Fort Bragg, NC
82d & 101st Airborne, 10th Mountain, 3d Infantry Divs
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
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…)
General Staff (G)
Joint Staff (J)
J-1 (Manpower and Personnel Directorate)
2- Military Intelligence
J-3 (Operations Directorate)
J-4 (Logistics Directorate)
5- Civil Affairs/ Military
J-5 (Strategic Plans and Policy Directorate)
6- Command, Control
and Communications Directorate
7- Operational Plans
and Interoperability Directorate
8- Force Structure,
Resources, and Assessment Directorate