U.S. Army Military Organization from Squad to Corps

A Guide to Each 'Building Block' in the Modern Army

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The elements in the organizational chart for the U.S. Army span the gamut from the individual soldier all the way to the largest building block commonly used, the corps. In between are the intermediate elements of Army organization, including the squad, platoon, company, battalion, brigade and division.

As you move through the organization, the elements become larger and also encompass more combat support units.

Typically, a company is the smallest Army element to be given a designation and an affiliation with higher headquarters at battalion and brigade level.

U.S. Army Military Organization from Squad to Corps

Here is a rundown of the various elements of command in the U.S. Army (information derived from Army Operational Unit Diagrams):

  • Squad/section. A squad, which is the smallest element in the Army structure, is typically made up of four to 10 soldiers and normally is commanded by a sergeant or staff sergeant. Some units have two squads that made up a section, commanded by a staff sergeant.
  • Platoon. Normally, a platoon includes 16 to 44 soldiers and is led by a lieutenant with an NCO as second in command. A platoon usually consists of three to four squads or sections.
  • Company. A company contains three to five platoons and a total of 60 to 200 soldiers. It's commanded by a captain with a first sergeant as the commander's principal NCO assistant. If the element is an artillery unit, it's called a battery rather than a company. If it's armored or air cavalry, it's called a troop. A company is a tactical sized unit and can perform a battlefield function on its own.
  • Battalion. This encompasses four to six companies and between 300 and 1,000 soldiers. A battalion normally is commanded by a lieutenant colonel, and a command sergeant major serves as principal NCO assistant. A battalion can conduct independent operations, if they're of limited scope and duration, and operates its own administration. An armored or air cavalry unit of equivalent size is known as a squadron.
  • Brigade. A brigade includes 1,500 to 3,200 soldiers, and a brigade headquarters commands the tactical operation of two to five combat battalions. Brigades normally are employed on independent or semi-independent operations, and normally are commanded by a colonel with a command sergeant major as senior NCO. In some cases, a brigadier general may assume command. Armored cavalry, ranger and special forces units in this size range are called regiments or groups instead of brigades.
  • Division. A division, with 10,000 to 16,000 soldiers, usually consists of three brigade-sized elements and is commanded by a major general, who is assisted by two brigadier generals. It can conduct major tactical operations and sustained battlefield operations and engagements. Divisions are numbered and are assigned missions based on their structures. Divisions perform major tactical operations for the corps and can conduct sustained battles and engagements.
  • Corps. A corps includes 20,000 to 45,000 soldiers and is made up of two to five divisions. It's normally commanded by a lieutenant general, who is assisted by a command sergeant major and an extensive corps staff. The corps provides the framework for modern multi-national operations.
  • Field army. A field army combines two or more corps, with 50,000 or more soldiers, and is typically commanded by a lieutenant general or higher-ranking officer. An army group plans and directs campaigns in a theater of operations, and includes two or more field armies under a designated commander. The U.S. Army hasn't used army groups since World War II.

More on Army Organizational Elements

The Army hasn't set a specific size to any specific element in its organizational chart. Instead, the number of soldiers in any given element of command depends on the type of unit involved and its mission.

For example, an aviation company would have a different number of troops assigned than an infantry company because it has a different mission, different equipment, and therefore different requirements.

The usual Army structure is battalion -> brigade -> division. Battalions that are organized into regiments are the exception. An example of this exception would be cavalry regiments. Cavalry is unique in that battalions are called "squadrons" and companies are called "troops."

However, most battalions that are actually part of brigades still have a regimental affiliation, such as 1/34 INF Rgt. 1st Battalion of the 34th. This affiliation is mainly historical and symbolic these days, and it has no real significance as far as the chain of command goes.

Up through the first part of the 20th century, a division was made up of two brigades, each of which had two regiments. This was called a "square" division. During World War II, the U.S. Army transitioned to "triangular" divisions of three brigades each (most other armies also had gone triangular during WW1). The Army accomplished this by cutting out the regiment level, but since the regiment traditionally was thought of as a soldier's "home," battalions kept their regimental designation even though the regiments as functional units no longer existed.

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