text: Armies, Corps, and Divisions
  employment of assigned, attached, and/or made available for tasking land forces; planning and coordinating
  land operations; or accomplishing such operational missions as may be assigned (JP 3-0). A JFC usually
  establishes a functional component command to conduct operations when forces from two or more Services
  must operate in the same physical domain or accomplish a distinct aspect of the mission. Normally, joint land
  operations involve multinational land forces. When these multinational forces fall under the command and
  control of the land component commander, they become a multinational joint force land component or
  combined force land component commander. These echelons can perform this role, but they require joint and
  multinational augmentation to perform effectively. (See JP 3-31 and Appendix B of this manual for in-depth
  information on joint force land component commanders.)
  Corps
  1-80. An Army corps is an echelon of command and tactical formations that employs divisions,
  multifunctional brigades, and functional brigades to achieve objectives on land (JP 3-31). The corps is the
  Army’s most versatile headquarters. The corps functions as one of the principal integrators of landpower into
  campaigns. When a field army is not present, a corps is the primary link between the operational and tactical
  levels of war. The corps is organized, manned, and equipped to serve in four roles:
  * Senior Army tactical formation in large-scale combat commanding two to five Army divisions
  together with supporting brigades and commands. This is its primary role.
  * ARFOR (with augmentation) within a joint force for campaigns and major operations when a field
  army is not present.
  * JTF headquarters (with significant augmentation) for crisis response and limited contingency
  operations.
  * Joint force land component (with significant augmentation) commanding Marine Corps and
  multinational divisions together with supporting brigades and commands.
  1-81. When serving under another echelon during multi-corps operations, the corps is a tactical command.
  When it is the only U.S. Army corps assigned to a higher echelon, it may serve as the ARFOR. When
  operating independently during large-scale combat, the corps may serve as the ARFOR or as the JFLCC, but
  it requires significant augmentation from the joint and multinational force to perform the latter role
  successfully. It may also form the nucleus for a JTF or JFLCC to respond to situations exceeding a division’s
  capability but not requiring more than one corps, although it would require joint force augmentation.
  1-82. Regardless of its role, the corps executes both operational and administrative responsibilities for its
  subordinate formations. (See Chapter 4 for a detailed description of the corps. For additional information on
  operational and administrative responsibilities, see ATP 3-92.)
  Division
  1-83. An Army division is an echelon of command and tactical formation that employs brigade combat teams,
  multifunctional brigades, and functional brigades to achieve objectives on land (JP 3-31). The division is the
  primary tactical formation in the Army. The division is organized, manned, and equipped to serve in four
  roles:
  * Tactical formation in large-scale combat capable of commanding two to five Army BCTs together
  with supporting brigades and commands. This is its primary role.
  * ARFOR (with augmentation) within a JTF in crisis response and limited contingency operations.
  * JTF headquarters (with significant augmentation) for crisis response operations and small limited
  contingency operations.
  * Joint force land component (with augmentation) under a JTF in crisis response and limited
  contingency operations not requiring more than one division.
  1-84. The division is a tactical unit of execution for a corps or field army. During large-scale ground combat
  and the consolidation of gains, the division is a tactical command that commands and controls multiple units
  to accomplish offensive, defensive, and stability tasks in its AO. Once the transition to competition begins
  and higher echelons redeploy, the division may assume the ARFOR or JFLCC role in an operational area for
  a limited duration, although this would require augmentation.