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21st Marine Regiment (United States)

The 21st Marine Regiment (21st Marines) was an infantry regiment of the United States Marine Corps. Activated for service in World War II, they fought in the battles of Bougainville, Guam and Iwo Jima. They fell under the 3rd Marine Division and were deactivated after the end of the war on December 20, 1945.[1]

21st Marine Regiment
Active1942 —45
CountryUnited States
BranchUnited States Marine Corps
TypeInfantry regiment
EngagementsWorld War II
* Battle of Bougainville
* Battle of Guam
* Battle of Iwo Jima
Robert Blake
Hartnoll J. Withers


Subordinate unitsEdit

The regiment was composed of three infantry battalions and one headquarters company:

Headquarters Company 21st Marines
1st Battalion, 21st Marines (1/21)
2nd Battalion, 21st Marines (2/21)
3rd Battalion, 21st Marines (3/21)


Fig. 1 Sketch of 21st Marines position after the first day of fighting on Guam.
Fig. 2 Yellow beach 1 and 2 would have been where the 21st deployed from.

The 21st Marine Regiment was activated on July 14, 1942, at Camp Elliot, San Diego, California, but was actually organized at New River, North Carolina.[2] Many of the first members of the regiment came from the 6th Marine Regiment. They were assigned to the 3rd Marine Division, however from January to June 1943 they were an independent regiment. During the war, the regiment took part in the Battle of Bougainville, Battle of Guam (Fig. 1) and the Battle of Iwo Jima. Following the Japanese surrender, 21st Marines moved to Guam where they were inactivated on December 20, 1945.[3]

Iwo JimaEdit

On Iwo the 21st RCT relieved the decimated 23rd on D-plus3[4] That placed the 21st in the 4th Marines ZofA assigned to yellow beach 2.(Fig. 2) The front lines were in the vicinities of Motoyama Airfields #1 and #2. On D-plus6 the Regiment reverted to the 3rd Marine Divisions control and was passed through by the 9th Marines.

Unit awardsEdit

Notable former membersEdit

Hershel W. Williams - Medal of Honor recipient

See alsoEdit


  1. ^ Rottman, Gordon L. (2002). U.S. Marine Corps World War II Order of Battle – Ground and Air Units in the Pacific War. Westport, Connecticut: Greenwood Press. p. 174. ISBN 0-313-31906-5.
  2. ^ Rottman, USMC WWII OOB, p. 134
  3. ^ Rottman, USMC WWII OOB, p. 174
  4. ^ [1]| C Co 1/23 WWII History
  5. ^ USMC Historical Monograph Guam, USMC History Division, Headquarters Quantico, VA.[2]