31st Marine Expeditionary Unit

Mission and Composition

MISSION: Provide a forward deployed, flexible sea-based Marine Air Ground Task Force (MAGTF) capable of conducting amphibious operations, crisis response and limited contingency operations, including enabling the introduction of follow on forces and designated special operations in order to support the theater requirements of the Geographic Combatant Commanders.

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Since World War II, in nearly every crisis in which the United States has deployed forces, the first military units in position to move ashore with sufficient sustainability for prolonged operations have been from one of America’s Fleet Marine Forces. These forces have been organized into Marine Air Ground Task Forces (MAGTF) – a combination of air, ground, and support assets.

MAGTFs are established for specific missions, or in anticipation of a wide range of possible missions. Combining air, ground, and logistics assets maximizes the combat power of each of the war-fighting elements. Tailoring of MAGTFs is based on detailed analysis of specific situations as well as historical data which has been compiled by Marine Corps planners over the past several decades.

MAGTFs have long provided the United States with a broad spectrum of response options when U.S. and allied interests have been threatened and in non-combat situations which require instant response to crisis. Selective, timely, and credible commitment of air-ground units has, on many occasions, helped bring stability to a region and sent signals world-wide to aggressors that the United States is not only willing to defend its interests, but able to do so with a significantly powerful force on extremely short notice.

The Marine Expeditionary Unit (MEU) is the smallest of the MAGTFs. Together with Navy counterparts, the MEU serves as the Nation’s forward deployed, quick response force, capable of accomplishing numerous missions around the globe.

The MEU, commanded by a Marine colonel, is comprised of approximately 2,200 Marines and Sailors embarked aboard three or four amphibious ships. These ships are manned by another 2100-2300 Marines and Sailors and as a group are designated as an Amphibious Squadron (PHIBRON) commanded by a senior Navy Captain, who bears the title of Commodore. Joined together, the MEU and PHIBRON are designated as an Amphibious Ready Group (ARG).

The 31st MEU, working with PHIBRON 11 and the USS America ARG, comprise one such Navy/Marine team. The 31st MEU and PHIBRON 11 are the only Forward Deployed Naval Force (FDNF) in the Asia-Pacific region.

The MEU’s major elements are the Command Element (CE), the Ground Combat Element (GCE), the Aviation Combat Element (ACE), and a Logistics Combat Element (LCE).

The CE is comprised of the Commanding Officer and supporting staff. It provides the command and coordination essential for effective planning and execution of operations. It also contains detachments that provide reconnaissance, intelligence, and electronic warfare capabilities. 

The GCE for the 31st MEU is a Battalion Landing Team (BLT), and rotates every 6 months as part of the Unit Deployment Program from Camp Pendleton, California. Currently, the 31st MEU's BLT is 3rd Battalion, 4th Marines. Based on an infantry battalion, the BLT is reinforced with artillery, Assault Amphibious Vehicles, combat engineers, an anti-armor section, and light armored vehicles. The mixture and number of pieces of such types of equipment are tailored to the mission – or anticipated missions – of the deploying MEU, and may be influenced by mode of transport.

The ACE for the 31st MEU rotates annually and is currently Marine Medium Tiltrotor Squadron 262 (Reinforced), which is reinforced with a detachment of F-35B Lightning II fighter aircraft from Marine Fighter Attack Squadron 121. The ACE provides rotary and fixed-wing air support. Composition is based on the tactical situation, the MAGTF's mission and size, and space limitations within the ARG.  

The ACE is capable of conducting a full range of Marine air operations and is comprised of appropriate Marine Aircraft Wing assets, which include rotary wing aircraft (helicopters) such as the CH-53E Super Stallion, MV-22B Osprey, UH-1Y Venom, and AH-1Z Viper, and fixed-wing aircraft (jets) such as the F-35B. The MEU also has two C-130 transport planes on standby at Marine Corps Air Station Futenma, Okinawa Japan. Additionally, to ensure self-sufficiency, the ACE has air traffic control, aircraft maintenance/support, and aviation logistics/supply.

The final major piece of the MEU is the LCE. For the 31st MEU, Combat Logistics Battalion 31 (CLB-31) is the permanent LCE. The mission of the LCE is to provide combat support. Specifically, this entails: supply, maintenance, transportation, explosive ordnance disposal, disbursing (pay services), water production and distribution, engineering, medical and dental services, fuel storage and distribution, and other services to the deployed MEU. Relatively small in numbers, usually with less than 300 Marines and Sailors, the LCE has a wide range of capabilities, with each Marine and Sailor contributing his own specialized skill to ensure that the personnel and equipment of the combat arms are ready for, and sustained through, combat or contingency operations.

The MEU is unique in that its air and ground combat elements are combined with combat service support under one commander – the MEU commanding officer. This air-ground task force concept is designed to thoroughly exploit the combat power inherent in air and ground assets by closely integrating them into a single force. It brings what it needs to sustain itself from the sea for the rapid accomplishment of the mission or to pave the way for follow-on forces.

The size and composition of the MEU makes it well-suited for amphibious combat operations as well as noncombat crisis response missions. The MEU is an expeditionary force in nature, able to operate in foreign lands without U.S. bases and facilities. It is also Naval in character, useful in conventional operations in the air and ashore, and is able to operate with U.S. fleets around the world. The MEU's combined arms team bears substantial force and is capable of a high degree of tactical mobility while delivering significant, sustained firepower within an objective area.

Prior to deployment each MEU is thoroughly trained in 10 Mission Essential Tasks (METS), ranging from humanitarian assistance to traditional amphibious assaults:

* Amphibious Raids (Small Boat, Combat Rubber Raiding Craft)

* Mechanized Amphibious Assaults (Assault Amphibious Vehicles)

* Security, Stability, Transition and Reconstruction Operations

* Support Theater Security Cooperation Activities

* Humanitarian Assistance (HA)

* Noncombatant Evacuation Operations (NEO)

* Tactical Recovery of Aircraft, Equipment, Personnel (TRAP)

* Airfield Operations from Expeditionary Sea or Shore Based Sites

* Airfield and/or Port Seizure Operations

* Joint and Combined Operations

Unique METS for the 31st MEU:

- Maritime Contingency Operations

- Visit, Board, Search, and Seizure (VBSS)

- Seizure of Maritime Platform and Selected Maritime Security Missions

- Limited Scale Raids

The 31st MEU is not a special operations force by definition, but because of the MEU's forward-deployed status in "hot spots" around the world, the MEU must be able to perform many types of missions in addition to conventional military warfighting. The MEU, through enhanced training, achieves the capability to accomplish selective maritime special operations. MEUs are capable of quick reaction – rapidly assembling required forces to accomplish missions, using intelligence-based operational decision making, and acting as a rapid response force.