Most U.S. Army units can be operationally divided into the following components from largest to smallest: •
Field army: Formerly consisted of an army headquarters battalion, two corps, army troops (including army field artillery and army air defense artillery groups and brigades, an armored cavalry regiment, army aviation, military intelligence, combat engineer, and signal groups, and brigades), and a field army support command (FASCOM) consisting of military police, medical, and support (i.e., maintenance, quartermaster, and services) brigades, and transportation and ordnance groups. Now primarily an administrative arrangement, consisting of multiple corps. The last time a multiple-corps army took the field was Third Army directing VII and XVIII Corps during
Operation Desert Storm. Armies now also operate as army service component commands (ASCCs) of unified combatant commands, such as Seventh Army/
USAREUR. Armies have also effectively operated as
military districts formerly in the continental United States. Fifth Army and First Army performed this function up until recently. Usually commanded by a
general or
lieutenant general. •
Corps: Formerly consisted of a corps headquarters and two or more divisions, corps troops (consisting of corps artillery, an armored cavalry regiment, an air defense artillery group, and an army aviation group), an expeditionary sustainment command (ESC) and other organic support brigades. A corps is now designated as an "operational unit of employment", that may command a flexible number of modular units. Usually commanded by a
lieutenant general. 20,000–45,000 soldiers. •
Division: Formerly consisted of a division headquarters company, three maneuver brigades, division artillery (DIVARTY), sustainment brigade, an aviation brigade, an air defense artillery battalion, an armored cavalry squadron, and an engineer brigade, and other support assets. Until the
brigade combat team program was developed, the division was the smallest self-sufficient level of organization in the U.S. Army. Current divisions are "tactical units of employment", and may command a flexible number of modular units, but generally will include three brigade combat teams and a
combat aviation brigade, supported by a staff in a headquarters and headquarters battalion. Usually commanded by a
major general who is supported by a
command sergeant major. Typically consists of 17,000–21,000 soldiers but can grow up to 35,000–40,000 with attached support units. •
Brigade (or group): Composed of three battalions, with a
brigadier general or a
colonel as commander, supported by a staff in a
headquarters and headquarters company. Maneuver brigades have transformed into brigade combat teams, generally consisting of three maneuver battalions, a cavalry squadron, a fires battalion, a special troops battalion (with engineers, signals, and military intelligence), and a
command sergeant major and a support battalion. Stryker brigade combat teams have a somewhat larger structure. 3,000–5,000 soldiers. •
Regiment: The Army, for the most part is no longer organized by regiments. Rather, battalions and squadrons maintain regimental affiliations in that they are called (for example), 1st Battalion, 8th Infantry (Regiment is implied) and is written 1–8 Inf. In this case, there is no regimental commander, and the battalion is organized as part of a brigade for combat. The exceptions are those units, such as armored cavalry regiments which remain organized, and fight, as a regiment and have a regimental commander. The written designation is easy to distinguish and commonly misused. A "forward slash" ("/") separates levels of command. 1st Squadron, 3rd Armored Cavalry Regiment is written 1/3 ACR whereas the 1st Battalion, 6th Field Artillery (again, Regiment is implied) is written 1–6 FA. •
Battalion (or cavalry
squadron): Normally composed of three companies, troops or batteries and led by a battalion/squadron commander, usually a
lieutenant colonel supported by a
command sergeant major and a staff in a
headquarters and headquarters company/battery/troop. 300–1,000 soldiers. •
Company (or
artillery battery/cavalry troop): Designated A to C (plus HQ or support companies/batteries/troops) when in a 3 company/battery battalion or A to D when organized in a 4 company/battery battalion. Regimental troops are designated A to T, depending on the number of troops. The troops are then divided into their like squadrons. Each company/battery/troop is composed of a company/battery/troop headquarters and three platoons, and led by a company/battery/troop commander, usually a
first lieutenant,
captain or sometimes a
major supported by a
first sergeant. 62–190 soldiers. •
Platoon: Composed of a platoon headquarters and three squads, led by a
platoon leader, usually a
second lieutenant supported by a
platoon sergeant (
sergeant first class). 42 soldiers. •
Section: Usually directed by a
sergeant supported by one or two corporals who supplies guidance for junior NCO squad leaders. Often used in conjunction with platoons at the company level. 12–24 soldiers. •
Squad: Composed of two teams and is typically led by a
staff sergeant or
sergeant. 9 soldiers. •
Team: The smallest unit. A
fire team consists of a team leader (usually a
sergeant or
corporal), a rifleman, a grenadier, and an automatic rifleman. A
sniper team consists of a
sniper who engages the enemy and a spotter who assists in targeting, team defense, and security. 4 soldiers. ==Major Operational Units==