During World War II, Fort McCoy was used as a concentration camp for approximately 170 Japanese and 120 German and Italian American civilians arrested as potentially dangerous "enemy aliens" in 1942. After the internees were transferred to other camps, McCoy was used as a training facility for units from across the country preparing to enter combat, including the segregated all-Nisei 100th Infantry Battalion. The post was also used as a prisoner-of-war (POW) camp during the conflict, holding 4,000 Japanese and German POWs. Fort McCoy's POWs were featured in the 2011 film "Fort McCoy".