Marine Unit Breakdown

Ground Combat Elements (GCE)

The basic organization of Marine Corps infantry units follows the “rule of threes”, which places three subordinates under a commander, not counting support elements. The organization and weapons are from the Marine Corps Table of Organization and Equipment (TOE) standard. Note that these are principles, but according to manpower and mission needs units can deviate from the TOE (e.g. with four subordinate units instead of three, or a commander who is a rank above or below the rank specified). Supporting units will have their own organization and equipment, but generally also follow the “rule of threes”. A GCE can be assigned to either colonies, starbases, or starships.

Marine GCE unit structure:

– A fire team is the basic element of the GCE. It consists of four Marines: the team leader/grenadier, two rifleman, and one special weapons infantryman. The team leader is typically a Corporal.
– A squad is made up of three fire teams, in addition to a Sergeant as squad leader. A squad is capable of integrating a variety of attachments from a weapons platoon.
– A rifle platoon consists of three squads, and a headquarters element made up of a Platoon Commander, a Platoon Sergeant and a Corpsman (there may be two Corpsmen in larger platoons). The Platoon Sergeant, usually a Staff or Gunnery Sergeant, advises the commander, usually a 2nd or 1st Lieutenant, in making decisions.
– A weapons platoon will substitute for the squads:

  • a mortar section (three squads, each equipped with a mortar and three Marines, all led by a section leader);
  • an assault section (three squads, each of two teams, which each consist of a Shoulder-fired Multipurpose Assault Weapon (SMAW) and two Marines), led by a section leader (thirteen Marines total); and
  • a medium grade weapons section (three squads, each of a squad leader and two teams) It is led by a 2nd or 1st Lieutenant.

– A rifle company consists of three rifle platoons, a weapons platoon, and support staff. It is led by a Captain, typically with a First Lieutenant as the Executive Officer and second in command.
– A weapons company will substitute for the rifle platoons a mortar platoon, an anti-armor platoon, and a heavy weapons platoon. A Headquarters and Service Company consist of a headquarters platoon, a communications platoon, a service platoon, and the Battalion Aid Station.
– A battalion consists of three rifle companies, one weapons company, and one Headquarters and Service Company, commanded by a Lieutenant Colonel.
– A regiment consists of three battalions, led by a Colonel
– A division, commanded by a Major General, comprises three infantry regiments and an artillery regiment, and additional specialized units, such as armor.
– A brigade, commanded by a brigadier general, is less common in the Marine Corps, but is typically made up of two or more regiments plus support units.

Battalions and larger units have a Sergeant Major, and an Executive Officer as second in command, plus officers and others for a military staff: Administration (S-1), Intelligence (S-2), Operations (S-3), Logistics (S-4), Civil Affairs (wartime only) (S-5), and Communications (S-6). Units of battalion size or larger may be reinforced by the addition of supporting tank or artillery units, as in the Battalion Landing Teams comprising the GCEs of Marine Expeditionary Units.
– A regiment consists of three battalions, led by a Colonel
– A division, commanded by a Major general, comprises three infantry regiments and an artillery regiment, and other specialized units as needed.

Ideal numerical breakdown of GCE units (numbers can vary +/- based on any number of factors)

Fire Team = 4
Squad = 12
Platoon = 38
Company = 116
Brigade = 350+
Battalion = 1052+
Regiment = 3150+
Division = 9450+