The 87th Mountain Infantry Battalion was activated on 15 November 1941 at Fort Lewis, Washington. This unit was the first American regiment of mountain troops. It was expanded into a regiment in 1943. On 12 May 1942, the regiment was reorganized as the 87th Mountain Infantry at Fort Lewis. The 87th joined the 10th Mountain Division at Camp Hale, Colorado and trained there during 1942–43.
Originally activated as the 10th Light Division (Alpine) in 1943, the division was redesignated the 10th Mountain Division in 1944 and fought in the mountains of Italy in some of the roughest terrain in World War II.
Following the war, the division was deactivated.
In 1942, soldiers trained at Camp Hale at an altitude of 2,800 meters to hone their combat and survival skills in the toughest mountain conditions.