Organization

Here is the typical organization for ground units:

• Fire team: four Marines
• Squad: three fire teams and a corporal or sergeant as squad leader
• Platoon: three squads, a platoon sergeant, and a lieutenant as platoon commander
• Company: three platoons, a Navy corpsman, a company gunnery sergeant, first sergeant, a first lieutenant as executive officer, and captain as commander
• Battalion: three or four companies, commanded by a lieutenant colonel
• Regiment: three or four battalions, commanded by a colonel
• Brigade: uncommon in the Marine Corps, but typically made up of one or more regiments and commanded by a brigadier general
• Division: three or four regiments, officers and others, commanded by a major general

Battalions and larger units have a sergeant major, and an executive officer as second in command, plus officers and others for: Administration (S-1), Intelligence (S-2), Operations (S-3), Logistics (S-4), Civil Affairs [wartime only] (S-5), and Communications (S-6).

As of 2004, there are four Marine divisions:

• the First in Camp Pendleton, California;
• the Second in Camp Lejeune, North Carolina;
• the Third in Camp Smedley Butler in Okinawa, Japan; and
• the Fourth is a reserve unit headquarted in New Orleans, Lousiania, with units scattered throughout the continental United States.

In World War II, two more Marine Divisions were formed: the Fifth and Sixth, which fought in the Pacific War. These divisions were disbanded after the end of the war.

Typical aviation units are squadron, group and wing. There are four Marine aircraft wings:

• the First in Okinawa, Japan;
• the Second in Marine Corps Air Station Cherry Point, North Carolina;
• the Third at Marine Corps Air Station Miramar, California; and
• the Fourth, a reserve unit.

There are also four Force Service Support Groups; the 4th FSSG is a reserve unit.

Air-ground task forces

The Marine Corps organization is flexible, and task forces can be formed of any size. Modern deployed Marine units are based upon the doctrine of the Marine air-ground task force, or MAGTF. A MAGTF can generally be of any of three sizes, based upon the amount of force required in the given situation; however, all MAGTFs have a similar organization.

A MAGTF is comprised of four elements: the command element (CE), the ground combat element (GCE), the air combat element (ACE) and the combat service support element (CSSE).

• Command element �?A headquarters unit that directs the other elements
• Ground combat element �?Usually infantry, supported by armor (tanks), and artillery, but including special units such as scouts or Force Reconnaissance, snipers and forward air controllers
• Air combat element �?The total airpower strength of the MAGTF, the ACE includes all aerial vehicles (both fixed wing and helicopter), their pilots and maintenance personnel
• Combat service support element �?This element includes all of the support units for the MAGTF: communications, combat engineers, motor transport, medical and supply units, and certain specialized groups such as air delivery and landing support teams

The smallest type of MAGTF is the Marine Expeditionary Unit (MEU). It is based upon a rifle battalion with usually an aircraft squadron (helicopters or both rotor- and fixed-wing) and an appropriately sized support unit attached. The specific makeup of the MEU can be customized based upon the task at hand—more artillery, armor, or air units can be attached, including squadrons of F/A-18 Hornet and Harrier jets.

There are usually three MEUs assigned to each of the U.S. Navy Atlantic and Pacific Fleets, with another MEU based on Okinawa. While one MEU is on deployment, one MEU is training to deploy and one is standing down, resting its Marines, and refitting. Each MEU is rated as capable of performing special operations.

A Marine Expeditionary Brigade (MEB) is larger than a MEU, and is based upon a Marine regiment, with larger air and support contingents.

A Marine Expeditionary Force (MEF), as deployed in Iraq in 2003, comprises a Marine division with an artillery regiment, several tank battalions, several LAV battalions, as well as an air wing. The [I Marine Expeditionary Force]] as deployed in the Persian Gulf War ultimately consisted of the 1st and 2nd Marine Divisions as well as considerable Marine air and support units.