Infantry Structure
The following article comes from Lt Col (USA, Ret.) Hugh Foster, historian. Used with permission.

26 April 2000


The basic weapon of the US Army has always been the individual infantry soldier with his rifle. He is the ultimate weapon. He meets the enemy eye-to-eye, defeats him on the battlefield, and occupies terrain. The structure of the entire US Armed Forces is designed to support this man in the accomplishment of his mission.

In World War II Generals Marshall (Chief of Staff of the Army) and McNair (Commander of the Army Ground Forces) “shared a common mental picture of how the enemy would be defeated. They imagined a comparative handful of men picking themselves up from the dirt and mud after spending hours lying on the ground; these were men who were wet, probably men shivering with cold; thirsty, hungry, tired and afraid, mentally scarred by the deaths of friends and by witnessing sights that would haunt them for the rest of their lives, they would move forward under machine gun and artillery fire. Some would fall, but the survivors would close with the enemy and kill him in a foxhole or a bunker, a building or a ditch, or die in the attempt. All the machinery the Army possessed came down in the end to that one-act drama. And it was that moment, repeated a million times over, that Army Ground Forces was created to produce.”

It was during World War II that the Combat Infantryman Badge (CIB) was instituted, at the suggestion of General Omar Bradley. The “Soldier’s General” felt strongly that the very special nature of infantry combat deserved unique recognition. Awards of the CIB and its only companion, the Combat Medical Badge (CMB), awarded only to aid men assigned to infantry units, began in 1944. These are the only such “combat” badges authorized. Regulations prescribe that these badges be worn above all other awards and decorations, including the ribbon of the Medal of Honor. Describing why he felt infantrymen should receive such an award, Bradley wrote: “The rifleman fights without promise of either reward or relief. Behind every river there’s another hill -- and behind that hill, another river. After weeks or months in the line only a wound can offer him the comfort of safety, shelter, and a bed. Those who are left to fight, fight on, evading death but knowing that with each day of evasion they have exhausted one more chance for survival. Sooner or later, unless victory comes this chase must end on the litter or in the grave.”

All the other branches of the Army and the other branches of the Armed Forces are indispensable in war; it is the combined effort of the whole that brings victory, but it is the infantry that determines victory. The simple soldier with his rifle and bayonet are at the head of the Army. He is the first to pierce the enemy line, and his final position marks the limits of ground actually taken. The infantry leads, the others follow. “If the bayonet could speak, what could it say but ‘FOLLOW ME.’

THE INFANTRY DIVISION (Authorized Strength, 1943-44 - 14,253):

The infantry division was the smallest Army organization deemed capable of conducting independent combat operations, as virtually all ground combat and support capabilities were possessed by units assigned to the division. (This is a very nice statement, but the fact is that divisions never operated without “outside” support and reinforcement.) The World War II infantry division was a “triangularized” division, its combat and support power based on groupings of “three’s,” beginning with the primary fighting organizations of the division -- the three infantry regiments. Other elements of the division, all designed to support the combat operations of the three infantry regiments, were grouped into categories known as “Division Artillery” and “Division Troops.”

Each division contained three battalions of light artillery (generally 105mm howitzers) and one battalion of medium artillery (155mm howitzers). Each light battalion, containing three 4-gun “firing batteries,” generally operated in direct support of one regiment, and the affiliation of a particular light artillery battalion to an infantry regiment generally became habitual. The medium battalion operated in general support of all three regiments, shifting its heavier, longer range firepower where need was greatest. The 105mm howitzer of WWII could fire a 33-lb high explosive projectile to a range of about 7,000 yards. To unprotected soldiers on flat terrain, a 105mm round was lethal to most soldiers within 30 yards of its impact, and could wound men to a distance of 500 yards. The 155mm howitzer fired a 95-lb projectile to a range of about 12,000 yards. Its killing radius was about 60 yards and its wounding radius was about 600 yards. Artillery was (and remains) the greatest killer on the battlefield.

The remainder of divisional organizations -- Division Troops -- provided the combat support and combat service support needed to sustain the division in both combat and administrative functions. These organizations were as follows:
 - Division Headquarters Company
 - Engineer Combat Battalion
 - Medical Battalion
 - Cavalry Reconnaissance Troop
 - Ordnance Company
 - Quartermaster Company
 - Signal Company
 - Military Police Platoon

Division Artillery and Division Troops accounted for nearly 5,000 of the division’s 14,253 soldiers. Much of this organization operated “well forward” in the battle area, and in fact many support troops operated within the regimental areas. (It should be pointed out here that artillerymen DO NOT consider themselves “support” troops in any sense of the word; they consider themselves “combat” troops, on an equal par with infantry and armor soldiers. [This despite the fact that the author has NEVER seen a bayonet lug on a howitzer barrel -- or a tank main gun barrel either, for that matter.])

All of the above-mentioned structure, including the regiments, was organized to support the relatively few riflemen who actually defended ground and seized it from the enemy -- the 2,916 men in the 243 infantry rifle squads of a division.

THE RIFLE SQUAD (Authorized Strength - 12):

Twelve infantrymen formed the rifle squad, the basic combat unit of the Army. Eleven of these soldiers were armed with the .30-caliber, semi-automatic M1 Garand rifle; one man carried a fully automatic Browning Automatic Rifle (BAR) that fired the same ammunition as the M1. A staff sergeant (squad leader) was in charge of the squad, and he was assisted by a sergeant (assistant squad leader). While both NCOs (Non-Commissioned Officers) were considered “shooters” they also had major duties to perform in leading the squad as a whole or parts of it, when the squad was divided into teams.

In both defensive and offensive operations, the squad’s actions were geared to the BAR, which provided the squad’s primary firepower. Two of the squad’s riflemen were assigned to support the BAR gunner, one as an assistant gunner and one as an ammunition bearer. In combat, the squad leader and his assistant directed the actions of seven riflemen and the three-man BAR team.

THE RIFLE PLATOON (Authorized Strength - 41):

Three rifle squads and a small headquarters cell together comprised the infantry rifle platoon, which was commanded by a lieutenant -- for as long as he survived. In addition to the platoon commander the headquarters was authorized a technical sergeant (platoon sergeant), a staff sergeant (platoon guide) and two messengers (privates), who were also called “runners.”

The rifle squads were numbered 1 - 3, as were the rifle platoons.

It was at the platoon level and above that “attachments” to the authorized strength and structure were commonly found. Each platoon normally was augmented by a medical aidman from the Regimental Medical Detachment. A mortar observer or observation team from the company’s weapons platoon or the battalion’s heavy mortar platoon might be attached for specific missions. In a similar fashion one or both of the company’s two light machine gun (air-cooled .30 caliber) teams or a heavy machine gun section (two water-cooled .30 caliber machine guns) might be attached to the platoon from the battalion’s heavy weapons company. The company commander also had five 3-man antitank rocket (“bazooka”) teams at his disposal, and he attached them to platoons as he saw fit. Under more rare conditions, engineers from the division’s engineer combat battalion might be attached.

THE RIFLE COMPANY (Authorized Strength - 193):

Three rifle platoons (1st, 2nd, and 3rd), a weapons platoon (sometimes called the 4th Platoon), and a company headquarters formed an infantry rifle company of six officers and 187 enlisted men, commanded by a captain. The weapons platoon (authorized strength - 1 officer and 34 enlisted men) contained two light machine gun squads and three 60mm mortar squads. (The 60mm mortar could lob a projectile about three times as powerful as a hand grenade out to a range of 2,000 yards. The great benefit of the mortar is that since its trajectory is very steep, it can be used to drop rounds behind hills, houses, etc. where the enemy would be protected from direct fire weapons.) The weapons platoon commander advised the company commander on disposition of the machine guns and mortars, which could be positioned to support the whole company generally, or to reinforce fires in a particular area of concern. Usually, the three mortars were grouped together in a single firing location. The two machine guns were doctrinally employed in “pairs” so that the fields of fire converged to cover as much of the company front as possible -- but this could be done with the machine guns positioned quite some distance apart.

The rifle company was the lowest level at which the unit was usually fielded in echelons, with components of the company not in physical contact with others. The rifle company normally operated in three echelons: the three rifle platoons and a portion of the company headquarters, including attachments; the three light, 60mm mortars of the Weapons Platoon, which tended to operate slightly to the rear of the “front line;” and the administrative portion of the company headquarters (cooks, clerks and supply personnel, totaling about 12 men) which usually operated from positions well to the rear.

At this level, too, attachment of outside resources was habitual. Routine attachments included platoon aid men for the rifle platoons, one or more heavy machine gun sections from the battalion’s heavy weapons company, a forward observer party (normally a lieutenant and two men) from the supporting artillery battalion, and a forward observer party (one or two men) from the mortar platoon of the battalion’s heavy weapons company. On occasion, antitank guns from the battalion’s antitank platoon or the regimental antitank company might be attached to a rifle company. The rifle company was also the lowest level infantry organization to employ a reserve force, usually one rifle platoon. It was at this level that the doctrine of “two up and one back” began (two thirds of a combat unit engaged and one third in reserve).

THE INFANTRY BATTALION (Authorized Strength - 860):

Three infantry rifle companies, a headquarters & headquarters company5, and a heavy weapons company together made up the infantry battalion. The headquarters & headquarters company was referred to by that name, or as “HHC”.  The other companies of the battalion, however, were known as the “letter companies.” Identification of the “letter companies” ran consecutively through the three battalions of the infantry regiment: 1st Battalion contained A, B, and C Companies (rifle companies) and D Company (heavy weapons); 2nd Battalion contained E, F, and G Companies (rifle companies) and H Company (heavy weapons); 3rd Battalion contained I, K, and L Companies (rifle companies) and M Company (heavy weapons). The letter J was not used, as it could be confused with the letter “I” when handwritten.

An infantry battalion headquarters & headquarters company (authorized strength - 126) contained the battalion’s headquarters cell, a company headquarters cell, a communications platoon, an ammunition & pioneer platoon, and an antitank platoon. Elements of this company operated all over the battle area in support of the battalion’s forward and rear command posts and the letter companies.

The heavy weapons company (authorized strength - 166) was designed to allow the battalion commander to add combat weight to the battalion in general, or to specific companies or parts of the battlefield. In addition to a headquarters cell, the weapons company contained two platoons of heavy machine guns (four .30 caliber water-cooled guns per platoon) and one 81mm mortar platoon of six guns. The 81mm mortar of WWII could lob a 15-lb high explosive projectile to a range of about 3,200 yards. The battalion commander generally apportioned the heavy machine guns to support particular rifle companies as he saw fit for specific situations, but usually retained the mortar platoon under the direct control of the battalion’s command group.

THE INFANTRY REGIMENT (Authorized Strength - 3,118):

An infantry regiment of an infantry division7 was composed of three infantry battalions (1st, 2nd and 3rd) and “regimental troops” consisting of a regimental headquarters & headquarters company, an antitank company, a cannon company, a service company, and a regimental medical detachment. Regimental identification was numerical, e.g., “15th Infantry Regiment”, but the numbers used were not necessarily consecutive within a division. Through a very complex and convoluted regimental assignment system, the regiments of a Regular Army division in WWII were never consecutively numbered, some of the regiments of a National Guard division were consecutively numbered, but all of the regiments of an Army Reserve division were consecutively numbered. For instance:
   - The 3rd Infantry Division (Regular Army) contained the 7th, 15th, and 30th Infantry Regiments
   - The 45th Infantry Division (National Guard) contained the 157th, 179th, and 180th Regiments
   - The 100th Infantry Division (Army Reserve) contained the 397th, 398th, and 399th Regiments

The regimental headquarters & headquarters company (authorized strength - 108) contained the regimental headquarters cell, a small company headquarters cell, a communications platoon, and an intelligence & reconnaissance platoon.

The regimental antitank company (authorized strength - 165) contained a large company headquarters, three antitank platoons of three wheeled 57mm cannon each, and an antitank mine platoon of three squads.

The regimental cannon company (authorized strength - 118) contained a headquarters section and three cannon platoons of two self-propelled (tracked) 105mm howitzers each. The Cannon Company usually operated from a single general location in support of the regiment, and was customarily grouped with the supporting field artillery battalion.

The regimental service company (authorized strength - 115) contained a company headquarters, a regimental headquarters platoon containing the regimental staff, and a transportation platoon that fielded 29 cargo trucks. The trucks were used to carry supplies and/or troops, but were not sufficient in number to move the entire regiment in a single lift.

The regimental medical detachment (authorized strength - 135) consisted of a headquarters section and a “battalion section” for each of the three infantry battalions of the regiment. The battalion sections established a medical aid station in each battalion sector and provided medical aid men to each rifle platoon and each heavy weapons platoon in the battalion. Litter teams were also assigned to the battalion sections, to evacuate the wounded from front-line areas to the aid station. Evacuation from the battalion aid stations was accomplished by ambulances sent forward from division.


Divisions were normally grouped into corps, also commanded by major generals, for commitment to combat. A corps consisted of at least two divisions, but usually contained several, at least one of which was an armored division. Divisions were “attached” rather than “assigned” to a corps and were frequently moved from corps to corps as the combat situation dictated. In theory, the corps was merely a tactical headquarters designed to carry out combat missions with whatever units were attached to it at any given time. In practice, however, a number of combat support and service support units were attached to each corps for such long periods that the “attachment” became de facto “assignment.” A corps usually commanded large components of heavy artillery, engineers, separate tank and tank destroyer battalions, quartermaster, ordnance, and medical facilities. The corps commander apportioned his assets to support his divisions in combat operations as the situation dictated, but each infantry division usually received attachment of a corps tank and tank destroyer battalion -- and the attachment of specific battalions soon became habitual with each infantry division. In keeping with the “two up and one back” doctrine that applied from infantry company upward, a corps tried to keep one division in reserve.

Corps were grouped under an “army” commanded, usually, by a lieutenant general. An army operated like a corps in that subordinate units were “attached” as required. Corps moved among and between armies, but the attached combat support and service support units attached to an army generally stayed with that army. An army sought to keep a corps in reserve, but was rarely able to do so.

When the number of corps and armies in a theater so dictated, armies were grouped into Army Groups of at least two armies. In western Europe, the forces under Eisenhower were arrayed in three army groups: the XXI, under Montgomery, in the north; the XII, under Bradley, in the center; and the VI, under Devers, in the south. Eisenhower commanded the European Theater of Operations, controlling not only the three army groups, but the naval and air components supporting them. Operations in Italy fell in the Mediterranean Theater of Operations, commanded by a British officer (he did not answer to Eisenhower).

The theaters of operations, including those in other parts of the world (such as the Pacific) were commanded and controlled by the Combined Chiefs of Staff -- and at this point I have exceeded my knowledge and interest.


In WWII the individual riflemen was supported in his mission by a seemingly overwhelming amount of combat and support power. But from his foxhole in the forest or jungle he could see only a few yards in any direction, and the vast majority of this support was not apparent to him. His squad was always short a few men, and he knew full well why those men were not there. His own machine guns, mortars, artillery, tanks and close air support were a sometimes-visible comfort, but they did not preclude him from having to advance with his rifle to meet the enemy -- who also had the support of machine guns, mortars, artillery, tanks and airplanes -- and defeat him “up close and personal” in encounters that left the survivors exhausted and shocked, their skin, clothing and equipment darkened by the accumulated grime of dirt, sweat and gunpowder.

The men in the combat elements of a rifle company faced a bleak future in which virtually everyone would be killed, wounded, injured, taken prisoner or felled by illness. That the soldiers who served the cause of freedom and fought so nobly for mankind and their comrades KNEW this dismal reality, yet soldiered on in spite of it is a wonder and a great testament to the character of the American GI of WWII, whose footsteps I followed with awe and great pride.
LTC, USA (Ret.)
Carlisle, PA

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