21st Marine Regiment (United States)

Commissioned for service during World War II, the regiment fought in the battles of Bougainville, Guam and Iwo Jima.

It fell under the command of the 3rd Marine Division and was decommissioned at the end of the war on December 20, 1945.

[1] The regiment was composed of three infantry battalions and one headquarters company: 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.

They were assigned to the 3rd Marine Division, however from January to June 1943 they were an independent regiment.

[3] 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.

3rd Battalion, 21st Marines on Iwo Jima. 24 February, 1945
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.