Army Force Structure (Corps, Division, Brigade)
The US_Army’s operating force is stacked in echelons: theater army → corps → division → brigade → battalion → company. The brigade combat team is the level that matters commercially, because it is the smallest formation designed to fight independently and therefore the unit in which most equipment is counted, priced, and fielded.
The echelons
Theater army. The ASCC assigned to a geographic combatant command. Sets the theater, does not maneuver.
Corps. A warfighting headquarters commanding multiple divisions. Four exist: I_Corps, III_Corps, V_Corps, and XVIII_Airborne_Corps. The Army_Transformation_Initiative moved them under theater armies — effective 5 December 2025, I Corps reassigned to USARPAC, III Corps to USAREUR-AF, and XVIII Airborne Corps to USAWHC.
Division. The Army’s principal tactical formation, roughly 15,000-20,000 soldiers, commanding two to five brigades plus a division artillery, sustainment brigade, and combat aviation brigade.
Brigade Combat Team (BCT). Combined arms at brigade scale: maneuver battalions plus organic fires, engineers, reconnaissance, and sustainment. Three legacy types — Armored (ABCT), Stryker (SBCT), and Infantry (IBCT) — plus the new Mobile BCT.
Current counts and the MBCT conversion
Per CRS for FY2026, the active component holds 11 ABCTs, 6 SBCTs, and 14 infantry/mobile BCTs, for 31 active BCTs, plus 11 combat aviation brigades and 2 Security Force Assistance Brigades (down from six).
The Mobile_Brigade_Combat_Team is the significant change. ATI directs converting all IBCTs — 14 active and roughly 20 ARNG — from about 4,500 soldiers to about 1,900, trading mass for mobility. The MBCT is built around the Infantry Squad Vehicle, organic unmanned aircraft, launched effects, and a new Multi-Function Reconnaissance Company that consolidates tactical UAS, electronic warfare, and effects platoons. Enabler units formerly habitual to the brigade engineer battalion move to brigade headquarters or up to division.
Why it matters
BCT counts are the denominator for almost every Army procurement quantity. A “one per squad” pitch multiplies differently against 31 BCTs of 4,500 than against a force of 1,900-soldier MBCTs, and the conversion changes both the count and the mix. It also creates new organic demand at echelons that previously had none: an MBCT with an organic UAS and EW company is a buyer of things an IBCT never bought. Cross-check any sizing claim against Program Elements and the fielding plan, not against the doctrinal table of organization.
See Also
US_Army · Total_Army · ASCC · ACOM · Army_Transformation_Initiative · Mobile_Brigade_Combat_Team · Combined_Arms_Warfare · Multi_Domain_Operations · Counter_UAS