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
IMEFlogo (2).png
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.
Operation Desert Storm
Global War on Terrorism
LtGen George W. Smith Jr.
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. George W. Smith Jr.[1] The deputy commander is Brig. Gen. Ryan S. Rideout.


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.


NATO Symbol
  • 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"


Structure of I MEF 2018


Recent serviceEdit

List of commandersEdit

Lt. Gen. Karsten S. Heckl, former commanding general, I Marine Expeditionary Force (MEF), passes the colors to Lt. Gen. George W. Smith Jr., signifying the change of command of I MEF during a formal ceremony on September 23, 2021.
No. Commander Term Ref
Portrait Name Took office Left office Term length
-Lieutenant General
Walter E. Boomer
(born 1938)
15 August 19906 September 19911 year, 22 days-
-Lieutenant General
Robert B. Johnston
(born 1937)
6 September 1991July 1993~1 year, 298 days-
-Lieutenant General
George R. Christmas
(born 1940)
July 1993July 1994~1 year, 0 days-
-Lieutenant General
Anthony Zinni
(born 1943)
July 1994October 1996~2 years, 92 days-
-Lieutenant General
Carlton W. Fulford Jr.
(born 1944)
October 1996April 1998~1 year, 182 days-
-Lieutenant General
Bruce B. Knutson Jr.
(born 1946)
April 19987 July 2000~2 years, 97 days-
-Lieutenant General
Michael W. Hagee
(born 1944)
7 July 200018 November 20022 years, 134 days[3]
-Lieutenant General
James T. Conway
(born 1947)
18 November 200212 September 20041 year, 299 days-
-Lieutenant General
John F. Sattler
(born 1949)
12 September 200414 August 20061 year, 336 days[4]
-Lieutenant General
James Mattis
(born 1950)
14 August 20065 November 20071 year, 83 days[5]
-Lieutenant General
Samuel T. Helland
(born 1947/1948)
5 November 200716 October 20092 years, 348 days[6]
-Lieutenant General
Joseph Dunford
(born 1953)
16 October 200919 October 20101 year, 3 days[6]
-Lieutenant General
Thomas D. Waldhauser
(born 1955)
19 October 201012 September 20121 year, 329 days[7]
-Lieutenant General
John A. Toolan
(born 1954)
12 September 201211 July 20141 year, 302 days[8]
-Lieutenant General
David H. Berger
(born 1959)
11 July 201427 July 20162 years, 16 days[9]
-Lieutenant General
Lewis A. Craparotta
(born 1959)
27 July 201630 July 20182 years, 3 days[10]
-Lieutenant General
Joseph Osterman
(born 1959)
30 July 201831 July 20202 years, 1 day[11]
-Lieutenant General
Karsten Heckl
(born 1964)
31 July 202023 September 20211 year, 54 days[12]
-Lieutenant General
George W. Smith Jr.
23 September 2021Incumbent227 days[13]


  1. ^ "I Marine Expeditionary Force". Retrieved 1 August 2020.
  2. ^ Reynolds Baghdad, Basrah and Beyond, pg. 169.
  3. ^ "Lieutenant General Michael W. Hagee, Commanding General, I Marine Expeditionary Force". U.S. Marine Corps. Archived from the original on 29 November 2001.
  4. ^ Sgt. Robert E. Jones Sr. (12 September 2004). "LT. GEN. SATTLER TAKES COMMAND OF I MEF". U.S. Marine Corps. Retrieved 16 May 2021.
  5. ^ Walker, Mark (15 August 2006). "Mattis assumes command of I Marine Expeditionary Force". The San Diego Union-Tribune. Retrieved 16 May 2021.
  6. ^ a b Cpl. Bobbie Curtis (22 October 2009). "Marine general caps a 41-year career at Camp Lejeune". Dvidshub.net. Retrieved 16 May 2021.
  7. ^ Cpl. Monty Burton (19 October 2010). "Dunford passes I MEF to Waldhauser". Dvidshub.net. Retrieved 16 May 2021.
  8. ^ Cpl. Jennifer Pirante (12 September 2012). "I MEF, MARCENT WELCOME NEW LEADERS". I MEF. Retrieved 16 May 2021.
  9. ^ Hlad, Jennifer (12 July 2014). "Change of command at Camp Pendleton's 1st Marine Expeditionary Force". Stripes. Retrieved 16 May 2021.
  10. ^ Fuentes, Gidget (28 July 2016). "Marine Corps' I MEF changes hands". USNI News. Retrieved 16 May 2021.
  11. ^ "LT. GEN. CRAPAROTTA COMPLETES TOUR AS I MEF COMMANDING GENERAL". U.S. Marine Corps. 24 July 2018. Retrieved 17 May 2021.
  12. ^ "I MARINE EXPEDITIONARY FORCE CHANGE OF COMMAND". U.S. Marine Corps. Retrieved 17 May 2021.
  13. ^ "I MEF Change of Command Ceremony 2021 [Image 7 of 7]". DVIDS. Retrieved 27 September 2021.

External linksEdit