On May 1, 1943, the 1st Battalion, 25th Marines was formed at Camp Lejeune, North Carolina, and was then shipped off to Camp Pendleton, California, to be assigned to the 4th Marine Division. During the war, the 1st Battalion, 25th Marines saw action in the following Island-hopping campaigns: Kwajalein, Battle of Saipan, Battle of Tinian, and the Battle of Iwo Jima. The battalion played a critical role in the seizure of Hill 382 (Turkey Knob) in an area that Marines on Iwo Jima called "the meat grinder". For its actions, the battalion earned a Presidential Unit Citation. The battalion saw no further action during the war due to having to rebuild the battalion after the heavy losses on Iwo Jima. The battalion was deactivated on October 31, 1945.