Theater Army

The Theater Army (TA) is normally the Army service component command in a unified command. The TA as the service component has both operational and support responsibilities. Its exact tasks are assigned by the theater CINC. These tasks may be exclusively operational missions, solely logistics tasks, or a combination of both types of responsibility.

The Theater Army commander is responsible to the unified commander for recommending how assigned US Army forces should be allocated and employed. The Theater Army commander's support responsibilities include the requirements to organize, equip, train, and maintain Army forces in the theater. The organization of a Theater Army is not standard. It varies between theaters according to the size of the US Army component in a force. It also varies with the factors of mission, enemy, terrain, troops, and time available (METT-T). Other levels of command can also perform TA functions. For example, a corps staff could perform the TA function if only a single corps were committed to a contingency area. On the other hand, a larger separate staff may be necessary to handle the administrative, legal, logistics, personnel, intelligence, operations, and communications tasks of a large force deployed overseas. Liaison between a Theater Army and another headquarters employing its forces must be performed whenever theater armies release operational control of their units.

Field Army	Theater Army
First US Army
Third US Army	US Army Central
Fifth US Army	US Army North
Sixth US Army	US Army South
Seventh US Army	US Army Europe

Echelon Above Corps [EAC] command levels are not easily distinguished, and may include both the Theater Army and the Numbered Field Army as separate headquarters. The Theater Army is primarily a departmental support headquarters, while the Numbered Field Army is a theater operational headquarters.

A theater of operations is normally divided into a combat zone and a communications zone. However, the situation and international agreements might dictate further breakdown of the combat zone into a forward and a rear combat zone.

The combat zone is that part of the theater of operations that the combat forces need to conduct operations. It contains the necessary organic combat support and combat service support facilities. It includes the geographical area extending from the rear boundary of the corps into the enemy-controlled area.

The COMMZ extends from the corps rear boundary to the theater boundaries designated by higher authority. The COMMZ encompasses the area to the rear of the combat zone. It includes the lines of communication, means for supply and evacuation, and the area required by the agencies and facilities that provide support to elements in the combat zone.

The major functional and area commands of the theater army in the COMMZ provide combat support and combat service support to Army forces and other services and agencies as directed. Combat service support provided includes support to the COMMZ, rear area protection in conjunction with the host nation if viable within the COMMZ, and support to the combat zone as directed by Theater Army [TA] headquarters.

There are five major subordinate commands that perform most of these functions. These commands are the personnel command, engineer command, transportation command, medical command, and TAACOM. The first four are functional commands that provide theaterwide combat service support to the theater army and other forces and activities as directed. The fifth subordinate command, formerly the TAACOM, has been redesignated the Theater Support Command.