Defense Primer: Department of the Army and Army Command Structure

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Updated October 10, 2024

Defense Primer: Department of the Army and Army Command Structure

Overview Defense Primer: Department of the Army and Army Command Structure

Overview

Article I, Section 8,Article I, Section 8 of the Constitution stipulates, “"The Congress shall have power ... to raise and support Armies ... make Rules for the Government and Regulation of the land and naval Forces ... for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel invasions.”

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The Department of the Army (DA) (Figure 1) is one of fourthree military departments reporting to the Department of Defense (DOD). The Army’, along with the Navy and Air Force, reporting to the Department of Defense (DOD), which is using "Department of War (DOW)" as a "secondary title" under Executive Order 14347, dated September 5, 2025. The Army's primary mission is to fight and win the nation’'s ground wars. The Army’s mission is both operational and institutional and is composed of four distinct components: the regular Active Component (AC), the reserve components of the United States Army Reserve (USAR), the Army National Guard (ARNG), and Department of the Army civilians (DAC). See Table 1.

• The Regular Army is the full-time, federal force of AC

soldiers.

• USAR is a federal reserve force that provides specialized

units and capabilities, as well as individual soldiers when mobilized.

• ARNG is a dual-status force that normally remains under

the command of state governors and can respond to domestic emergencies, unless its units are mobilized for a federal mission.

• DAC are federal government workers who fill a variety of

support roles.

Table 1. Army Components

Component

Total

Number

Location

TotalNumber Location(CONUS/OCONUS)

AC

448,276

396,586 / 51,690

USAR

170,601

163,262 / 7,339

ARNG

328,084

316,742 / 11,342

DAC

223,386

212,364 / 11,018

Source: Defense Manpower Data Center, as of June 30, 2025.

(CONUS/OCONUS)

AC 440,127 392,897/47,230

USAR 175,122 167,945/7,177

ARNG 323,377 314,693/8,684

DAC 229,121 217,943/11,178

Source: DMDC as of June 30, 2024.

Note: CONUS = Continental United States and OCONUS = Outside of the Continental United States (overseas).

Army

Senior Leadership The DADepartment of the Army is led by a civilian Secretary of the Army (SECARMY) appointed by the President with the advice and consent of the Senate. The SECARMY Secretary of the Army reports to the Secretary of Defense (SECDEF), who is using "Secretary of War" as a "secondary title" under Executive Order 14347, dated September 5, 2025, and serves as civilian oversight for the Army and Chief of Staff of the Army (CSA). The CSA is an administrative position held by a four-star Army general and is a statutory office (10 U.S.C. §3033)7033). The CSA is the chief military advisor and deputy to the SECARMYSecretary of the Army and, by statute (10 U.S.C. §151),, serves as a member of the Joint Chiefs of Staff (JCS). The JCS is composed of DOD’s 's (DOW's) senior uniformed leaders who advise the President, SECDEFSecretary of Defense (War), and Cabinet officials on military issues.

Command Authority

The Secretary of the Army's and the Chief of Staff of the Army's authorities are prescribed by law: 10 U.S.C. §7013 for the Secretary of the Army and 10 U.S.C. §7033 for the Chief of Staff of the Army. The CSA does not have operational command authority over deployed Army units. Under 10 U.S.C. §162, the operational chain of command runs from the President to the Secretary of Defense (War) and then to the commanders of the unified combatant commands, with the Chairman of the Joint Chiefs of Staff (CJCS) serving as the principal military advisor rather than a commander of forces. The CSA does, however, exercise supervision of Army units and organizations as designated by of the Secretary of the Army.

, and Cabinet officials on military issues.

Operational and Institutional Missions The operational Army—known as the Operational Force— conducts or directly supports military operations and consists of numbered armies, corps, divisions, brigades and battalions. The majority of the Army is based in the continental United States (CONUS) relying on forward- stationed and rotational units outside the continental United States (OCONUS) to deter potential enemies, train allies, and defend against aggression if needed.

The institutional Army supports the operational Army by providing the training, education, and logistics necessary “"to raise, train, equip, deploy, and ensure the readiness of all Army forces.”." Army organizations whose primary mission is to generate and sustain the Operating Forces, such as the Army Training and Doctrine Command (TRADOC) and Army Materiel Command (AMC), for example, are part of what is known as the Generating Force.

.

Army Command Structure There are three types of commands: Army Commands, Army Service Components Commands (ASCCs), and Direct Reporting Units (DRUs).

Army Commands. Army commands perform many Title 10 functions across multiple disciplines. The four Army Commands include Army Forces Command (FORSCOM), Army Futures Command (AFC), AMC, and TRADOC.

Army Service Components Commands (ASCCs).

Proposed Army Command Structure Changes: 2025 Army Transformation Initiative (ATI)

In May 2025, Army leadership announced the Army Transformation Initiative (ATI), with one of its initiatives to optimize force structure. Included in ATI's plans is a merger of Army Futures Command (AFC) and Training and Doctrine Command (TRADOC) into a single command under a single headquarters. Also under ATI, Forces Command (FORSCOM) is to transform into Western Hemisphere Command through the consolidation of Army North and Army South.

New Command Activations

As a result of ATI, the Army activated two new commands.

U.S. Army Transformation and Training Command

On October 1, 2025, the U.S. Army Transformation and Training Command (T2COM) was established as an Army command under the jurisdiction of Headquarters, Department of the Army by consolidating TRADOC and AFC.

U.S. Army Western Hemisphere Command

On December 5, 2025, the Army activated the U.S. Army Western Hemisphere Command (USAWHC) merging FORSCOM, U.S. Army North, and U.S. Army South into a single four-star headquarters. By February 2026, USAWHC is planned to reach initial operational capability (IOC) and full operational capability (FOC) by summer 2026. On December 2, 2025, the Army announced the following unit reassignments, effective December 5, 2025:

• I Corps was reassigned to United States Army Pacific (USARPAC);
• III Corps was reassigned to United States Army Europe-Africa (USAREUR-AF);
• XVIII Airborne Corps, First Army, 20^th Chemical, Biological, Radiological, Nuclear, and Explosives Command, and Air Traffic Services Command were reassigned to USAWHC; and
• 4^th Infantry Division was reassigned to the I Corps.

Army Commands

Army commands perform many Title 10 functions across multiple disciplines. At present, the three Army Commands include Army Forces Command (FORSCOM), Transformation and Training Command (T2COM), and Army Material Command (AMC).

Army Service Component Commands (ASCCs)

ASCCs are operational organizations aligned with combatant commands. The ASCC commander is responsible for advising the combatant commander on the allocation and employment of Army forces within athe combatant command. There are nine ASCCs, with five ASCCs aligned with geographic combatant commands and the remaining four ASCCs aligned with functional combatant commands, including U.S. Army Cyber

Relevant Statutes

Title 10, U.S. Code, Subtitle B, Armed Forces: Army

Title 10, U.S. Code, Subtitle E, Reserve Components

Title 32, U.S. Code, National Guard

Defense Primer: Department of the Army and Army Command Structure

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Command, Military Surface Deployment and Distribution Command, U.S. Army Space and Missile Defense Command, and U.S. Army Special Operations Command.

Direct Reporting Units (DRUs). . According to the Army, as a result of ATI, these ASCCs are to include

U.S. Army Central (USARCENT);

U.S. Army Europe and Africa (USAREUR–AF);

U.S. Army North (USARNORTH) (reassigned to USAWHC);

U.S. Army Pacific (USARPAC);

U.S. Army South (USARSOUTH) (reassigned to USAWHC);

U.S. Army Cyber Command (USARCYBER);

U.S. Army Transportation Command (ARTRANS);

U.S. Army Space and Missile Defense Command (USASMDC); and

U.S. Army Special Operations Command (USASOC).

Direct Reporting Units (DRUs)

DRUs have institutional or operational functions and provide broad, general support to the Army. There are 13 DRUs:

• According to the Army, as a result of ATI, these 15 DRUs are to includeU.S. Army Acquisition Support Center (USAASC);

•

U.S. Army Audit Agency (USAAA);

Arlington National Cemetery (ANC);

• Civilian Human Resources Agency (CHRA);

• U.S. Army Corps of Engineers (USACE);

•

U.S. Army Corrections Command (ACC);

U.S. Army Criminal Investigation Division (USACID);

• U.S. Army Human Resources Command (HRC);

• U.S. Army Intelligence and Security Command

(INSCOM);

• (INSCOM); U.S. Army Joint Counter–Small Unmanned Aircraft Systems Office (JCO); U.S. Army Medical Command (MEDCOM);

• U.S. Military Academy (USMA);

• U.S. Military District of Washington (MDW);

• Military Postal Service Agency (MPSA);

• and

U.S. Army Test and Evaluation Command (ATEC).

U.S. Army Test and Evaluation Command (ATEC);

and

• U.S. Army War College (AWC).

Figure 1. Department of the Army

Source: Association of the United States Army (AUSA), Institute of Land Warfare, Profile of the United States Army, September 2024, p. 11 at https://www.ausa.org/publications/profile-united-states-army-2024. Note: This publication is updated and published every two years, and it “serves as an introduction to the structure, purpose and activities of the entire Army.”

Barbara Salazar Torreon, Senior Research Librarian

Andrew Feickert, Specialist in Military Ground Forces

IF10544

CRS Products

CRS In Focus IF10571, Defense Primer: Organization of U.S. Ground Forces, by Barbara Salazar Torreon and Andrew Feickert.

CRS In Focus IF10540, Defense Primer: Reserve Forces, coordinated by Kristy N. Kamarck.

Other Resources

Department of the Army Budget Materials at https://www.asafm.army.mil/Budget-Materials/.

Understanding the Army's Structure at https://www.army.mil/organization/

Defense Primer: Department of the Army and Army Command Structure

https://crsreports.congress.gov | IF10544 · VERSION 12 · UPDATED

Disclaimer

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