The I Marine Expeditionary Force, or I MEF (pronounced “One M-E-F”) was activated on 8 November 1969 on the island of Okinawa with a goal of creating a military force that could deliver a rapid military response involving substantial air and ground assets. The unit was redesignated as the I Marine Amphibious Force the following August and then relocated to Camp Pendleton in April 1971; it was not until February 1988 that it was redesignated under its original title of I Marine Expeditionary Force.
Classified as a Marine Air Ground Task Force, the I MEF is divided into four main elements. The 1st Marine Division acts as the primary ground combat element and consists of four Marine Regiments and several types of support battalions (HQ, reconnaissance, light armored reconnaissance, combat engineers, tank, amphibian assault). The 1st Marine Logistics Group comprises two Combat Logistics Regiments, one including a Transportation Battalion and another with a Maintenance Battalion (1st Maintenance) and a Supply Battalion (1st Supply), while its regimental HQ has three Combat Logistics Battalions attached to it. Other unit types in the Logistics Group include Engineer, Medical, and Dental Battalions.
Aviation support, including fighter and strike capabilities, is the responsibility of the 1st Marine Aircraft wing. Rounding out the force is the 1st Marine Expeditionary Brigade; the 1st Marine Information Group, which contains various support battalions (Intelligence, Communication, Radio, Law Enforcement, Naval Gunfire Liaison); and three Marine Expeditionary Units.
The Logistics Group and Marine Division are headquartered at Camp Pendleton, California and the Aircraft Wing is based at Marine Corps Air Station Miramar in San Diego.