What does it mean when a newspaper mentions A company, 101st Airborne Division? How about 3/7 Cavalry? Is there a difference between a 'troop' and a 'group'? If you've never been in the US Army, these terms are probably confusing. Unit designation in the military have specific meanings that can help you understand what the unit is, how large it is and what it does.

There are standard ways of referring to units in the Army. A soldier could say that he was in 2nd Squad, 1st Section, Mortar Platoon, Headquarters and Headquarters Company, 1st Battalion (Mechanized), 5th Infantry Regiment, 3rd Brigade, 2nd Infantry Division, 8th US Army, but that would be long and overly complicated. There are various shortcuts that will help people understand where a soldier was stationed. For instance, the soldier who was in that unit could say, 'I served in the mortar platoon, 1/5 Infantry when I was in Korea,' which conveys almost as much information.

Soldiers wear patches on their left shoulder to show which unit they're in. They're called Shoulder Sleeve Insignia (SSI). Usually, only separate brigades or larger units will have SSIs. Much of the time, when you ask a soldier who he served with, he'll refer to the unit whose patch he wore. For example: 'When I was in Desert Storm, I served with the 24th Infantry Division.' In some circumstances, a more specific answer is called for, and the soldier will identify his company. To identify a numbered company, you refer to the number and the company (eg, 202nd Ordnance Company (EOD)). If the company is part of a battalion then you refer to the letter of the company and the battalion. 'Easy Company 1st of the 506th' would refer to someone in E Company, 1st Battalion, 506th Infantry¹.

Many units will have part of their name in parenthesis. The words in parenthesis differentiate different kinds of units within the same branch. For instance, the 4th Infantry Division (Mechanized) is very different from the 25th Infantry Division(Light). A mechanized infantry unit consists of mounted infantry who go to the battle in vehicles like the M-2 Bradley Infantry Fighting Vehicle. Mechanized infantry divisions are almost half mechanized infantry and half armor. A light infantry division is made up soldiers who walk to where they fight. If they're lucky, they may be transported by truck or helicopter to somewhere close to the battlefield.

Armies throughout the world use some of these same terms to describe their units. While there is some equivalence from one country to another, these terms are not always the same. American units tend to be larger than units from other countries that have the same title. For instance, a battalion in organized along Soviet lines² will have at most two–thirds as many people as an American battalion. Sometimes the terms are used for completely different things. An American squadron refers to a battalion level organization. A French squadron is a company level organization. A US Air Force squadron can refer to an organization with a hundred men or a thousand men.

Generally, US Marine Corps (USMC) units are about the same size as US Army units of the same name. USMC Non-Commissioned Officers (NCOs) have different titles and usually take on greater responsibilities at lower ranks. For instance, an Army sergeant would lead a fire team, whereas a Marine corporal would lead a fire team.

Regimental System

In 1984, the Army implemented the Combat Arms Regimental System (CARS). The regiments represent the historical lineage of units in the Army. These regiments are not usually units that are deployed in the field. They're split into battalions that are usually spread through different brigades and divisions in the Army. For instance, the

1st Bn (Air Assault), 503rd Infantry Regiment

is part of the 2nd Infantry Division in Korea and

2nd Bn (Airborne), 503 Infantry Regiment

is part of the

173rd Infantry Brigade (Airborne)

in Italy. There are some regiments that still fight as one unit in the cavalry and airborne infantry.

For convenience sake, Regiment is often dropped from the name of a unit, so the 24th Infantry refers to the 24th Infantry Regiment not the 24th Infantry Division (Mechanized). The Marines use the same convention. If someone referred to the 5th Marines, they're referring to the 5th Marine Regiment.

Reflagging Units

From time to time, units are redesignated. They retire the colors of an old unit, and take on the colors of a new one. This is called reflagging. In the Army's draw down in the mid-90s, the Third Infantry Division (Mechanized) in Germany was being closed down. Their colors were retired, and its units were dispersed. In order to perpetuate the unit, it was decided to reflag the 24th Infantry Division (Mechanized) at Fort Stewart, Georgia USA. At Fort Stewart, the soldiers of the 24th ID, who had recently returned from Desert Storm, cased there old colors. They uncased the colors of the Third Infantry Division.

Reflagging is not an unusual event. It's done for a variety of units. It's often done to keep the unit alive, and perpetuate the history of distinguished units. Sometimes it's done when force structure changes. In 1995, the Army Explosive Ordnance Disposal (EOD) field was restrucured. It had been made up detachments. Adminsited by regional control teams, who were overseen by an office at Forces Command (FORSCOM). The detachments were transformed into companies, the control teams were made battalions, and the office at FORSCOM was turned into the 52nd Ordnance Group (EOD).

Units

Squad

For all practical purposes, a squad is the smallest unit in the Army. A typical rifle squad will consist of about 10 men and it will be led by a staff sergeant. These may be further broken down into fire teams of four men led by a corporal or a sergeant. Squads in other units may vary in size. When units are mounted, squads are usually assigned one per tank, Bradley, or track. They will often have fewer people than an infantry squad. An M1A2 Abrams tank is crewed by four people and is usually led by a staff sergeant tank commander. A mortar squad will usually have four or five soldiers, and be led by a corporal or sergeant.

Section

Sections are a collection of soldiers; sometimes it will consist of several squads. Sections don't have any standard size, and they vary widely. A mortar section consists of three mortar squads, a fire direction center and is led by a staff sergeant. There are two mortar sections in a mortar platoon. A cavalry section in a Bradley unit will consist of two Bradley Cavalry Fighting Vehicles. The senior Bradley commander on the two Bradleys is the section leader. There are three sections in a Cavalry platoon.

Platoon

Platoons are a collection of squads. A typical infantry platoon will usually have four squads and about forty soldiers. Platoons are led by a lieutenant who assisted by a platoon sergeant who holds the rank of sergeant first class. There are generally three or more platoons per company.

Company

Companies (Co) are another basic building blocks of the Army. Companies are usually commanded by captains, although smaller companies may be commanded by lieutenants and some aviation companies are commanded by majors. Unit commanders will be assisted by a first sergeant. Infantry companies usually have around 200 soldiers, but the size of a company can vary between 15 to almost 500 soldiers. There are several different types company level organizations. Small or specialized units may be called detachments. Instead of having companies, the cavalry has troops and the field artillery and air defense artillery have batteries.

Separate company will be numbered such as 723 Ordnance Company (EOD). Companies that are part of battalions or regiments are usually referred to by a letter (eg A Co, 3/32 Infantry). Most battalions and higher level organizations will have a headquarters unit. This will usually be a Headquarters and Headquarters Company (HHC). Depending on the type of unit (Cavalry, Artillery, or Support) the headquarters unit may be a Troop (HHT), Battery (HHB), or Detachment (HHD). These companies will handle administrative functions for the battalion staff and usually command the battalions organic support units, like a mortar platoon, scout platoon, or maintenance platoon. There are usually four line companies plus an HHC per battalion.

Battalion

Battalions (Bn) are a basic building block in the military. They are commanded by Lieutenant Colonels and they are assisted by a command sergeant major³ and a battalion staff. Battalion level organizations may also be referred to as squadrons in cavalry units. Most combat arms battalions are referred to by their battalion and regimental numbers, like 1st Bn, 5th Infantry or 3rd Squadron, 7th Cavalry. This is usually abbreviated to 1-5 Infantry or 3/7 Cav. Battalions in combat support and combat service support branches will usually be identified by a number like 187th Ordnance Battalion (EOD) or the 924th Military Police Battalion. There are usually three battalions in each brigade.

Brigade

Brigades (Bde) consist of more than one battalion, and they are commanded by Colonels. There are several different brigade level organizations. There are regiments, like the 11th Armored Cavalry Regiment; and groups, like the 5th Special Forces Group (Airborne). Most infantry and armor brigades or organic to divisions. While these brigades may have a lineage of separate brigades, they are referred to by which brigade they are in the division, such as 1st Brigade, 4th Infantry Division (Mechanized). There are some separate maneuver brigades, like the 173rd Airborne Brigade. Separate have their own support units, while brigades that are part of divisions will be supported by division support units. Brigades are the highest level of organization that non-combat units have. Brigades are also the lowest level organization that might have shoulder sleeve insignia (SSI).

Division

Divisions are large units of about 15,000 soldiers that are commanded by Major Generals. They usually consist of three maneuver brigades, one aviation brigade, division artillery (which in turn consists of three artillery battalions), division support command, and several other support units. Divisions may be Airborne, Infantry, Armor, or Cavalry Divisions. The difference between a mechanized infantry division and armor division is the designation of one of the battalions as armor or infantry. The manuever units in a light infantry or airborne division is almost all leg infantry. There are some generic divisions, like the 78th Division (Training Support), in the reserves that are used for training activities like basic training. Examples of division units include the famed 82nd Airborne Division, 3rd Infantry Division (Mechanized), and 1st Armored Division. For convenience sake, infantry division is often shortened to ID (eg 3rd ID).

Corps

Corps are made up of two or more divisions. They are commanded by Lieutenant Generals. They are identified by roman numerals, such as V Corps (is spoken as '5 Corps,' rather than 'Fifth Corps'). Corps are not usually identified as a type of Corps. They're generic because they combine different kinds of divisions and support units. The only exception to this is the XVIII Airborne Corps, which has many airborne units and several non-airborne units.

Army

Numbered US Armies are usually made up of one or more corps. They may also be an Army unit responsible for a certain area. The Eighth Army is the army component of United States Forces Korea. It's only major sub-unit is the 2nd Infantry Division. The 3rd Army is the Army component of Central Command. During the 1991 Gulf War, it was made up the XVIII Airborne Corps and VII Corps. Armies are usually commanded by Generals.

Army Group

An Army Group is a collection of armies. The US Army hasn't used this designation since World War II.

Commands

While the list above covers the traditional units, there are many non-traditional units. There are commands, like the 1st Corps Support Command a unit with 10,000 soldiers that supports the XVIII Airborne Corps. Commands can be of different sizes. Forces Command (FORSCOM) is in overall command of all operational units in the Continental United States (CONUS). Training and Doctrine Command (TRADOC) is responsible for all Army schools and for developing the way the Army fights. In addition to commands, there are numerous other kinds of units, schools, activities, offices, etc throughout the Army.

Nicknames and Call Signs

There aren't named units in the Army like the Iraq's Medina Division, but most units have nicknames, mottos or call signs. The 101st Airborne Division (Air Assault) is known as the Screaming Eagles.

Every unit, and almost every individual, in a theatre of operations will have a radio call sign. They're made by designations for a unit and for a person's lace in that organization. These designations are in letter and number combinations that will look like A2N32d. On nets inside units, they can drop the front two letters.

For even greater ease, units usually use familiar call signs on internal radio nets. These consist of unit nicknames and a number that says who does what. 69th Armor has a panther on it's crest, so the commander of 3rd Battalion, 69th Armor might use a unit call sign of Panther for Battalion elements. Subordinate units will also pick or be assigned, during Desert Storm, E Company 3 Battalion, 15th Infantry was attached to 3/69 Armor. Their nickname was Chainsaw. The numbers are a fairly uniform throughout the Army. 6 represents the commander, 5 represents the executive officer (XO), etc. Therefore, if the commander of E Co, 3/15 Infantry wanted to call the XO of 3/69 Armor, he would call, "Chainsaw 5 to Panther 5."