I Marine Expeditionary Force

The I Marine Expeditionary Force ("I" pronounced "One") is a Marine Air Ground Task Force (MAGTF) of the United States Marine Corps primarily composed of the 1st Marine Division, 3rd Marine Aircraft Wing, and 1st Marine Logistics Group. It is based at Marine Corps Base Camp Pendleton.

I Marine Expeditionary Force
I MEF insignia
Active8 November 1969  present
Country United States of America
Branch United States Marine Corps
TypeMarine Air-Ground Task Force
RoleExpeditionary combat force
Part ofU.S. Marine Forces Pacific
Garrison/HQMCB Camp Pendleton, California, U.S.
EngagementsPersian Gulf War

Global War on Terrorism

Iraq War

Lieutenant General Joseph L. Osterman
Gen Joseph F. Dunford, Jr., Gen Anthony Zinni, Gen Michael Hagee, Gen James T. Conway, Gen James Mattis, Gen John F. Sattler

I Marine Expeditionary Force is the largest of the three MEFs in the Fleet Marine Force and is often referred to as the "Warfighting MEF" for its consistent involvement and contributions in major armed conflicts. It is presently commanded by Lt. Gen. Joseph Osterman.[1] The deputy commander is Brig. Gen. Rick Uribe.[2]


Pronunciation of the Roman numeral designator: As a Roman numeral the capital letter "I", representing one (1), is properly pronounced as "One." However, there are some who erroneously pronounce the number as either "First," or either intentionally, or unknowingly, pronounce it as "Eye," as in the letter "I."

The convention of using Roman numerals to designate a MEF, which is itself the Marine Corps equivalent organization to an Army corps, stems from the U.S. Army practice that began in the American Civil War, and continues today, of numbering corps (two or more divisions with supporting troops, and sometimes including separate brigades, regiments, groups, or battalions, all under a unified corps headquarters, usually commanded by a lieutenant general) with Roman numerals. Corps, themselves being the first-level sub-unit of a "field army," or a numbered, or named, army (e.g., First U.S. Army, or the Army of the Potomac).

During the First World War, the 4th Marine Brigade, as part of the U.S. Army 2nd Infantry Division, came under the U.S. Army I Corps, American Expeditionary Forces. With the expansion of the Marine Corps to six divisions and five air wings during the Second World War, the Marine Corps created two "Amphibious Corps," I Marine Amphibious Corps (later re-designated as III Amphibious Corps) and V Amphibious Corps, continuing the custom begun by the Army. Modern Marine Expeditionary Forces, or MEFs (for a time known as Marine Amphibious [italics added] Forces, or MABs) continue the U.S. Marine Corps legacy as corps-equivalent organizations designated by Roman numerals.


When directed, I MEF deploys and is employed as a Marine Air Ground Task Force (MAGTF) in support of Combatant Commander (COCOM) requirements for contingency response or Major Theater War; with appropriate augmentation, serves as the core element of a Joint Task Force (JTF); prepares and deploys combat ready MAGTF’s to support COCOM presence and crisis response; and supports service and COCOM initiatives as required.


  • Activated on 8 November 1969 at Okinawa, Japan as the I Marine Expeditionary Force
  • Redesignated on 18 August 1970 as the I Marine Amphibious Force (I MAF)
  • Relocated in April 1971 to Camp Pendleton, California
  • Redesignated on 5 February 1988 as the "I Marine Expeditionary Force"



Recent service


  1. "I Marine Expeditionary Force". Retrieved 31 July 2018.
  2. South, Todd (5 July 2018). "Marine one-star cited for misusing aide, taking gifts from subordinates". Marine Corps Times. Brig. Gen. Rick Uribe now commands I Marine Expeditionary Force at Camp Pendleton[...]
  3. Reynolds Baghdad, Basrah and Beyond, pg. 169.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.