Although this subseries is composed of two sub-subseries, the bulk of this subseries contains materials regarding the 442nd Infantry Regiment and 100th Infantry Battalion. Both units were primarily composed of Japanese American soldiers from Hawaii. The 100th Infantry Battalion was formed in 1942 of Japanese American soldiers from the 298th and 299th Infantry Regiments of the Hawaii National Guard. The 442nd Infantry Regiment was formed in 1943 as a Japanese American combat unit. Eventually, in 1944, the 100th Infantry Battalion became a part of the 442nd. Further information on the role of Americans of Japanese Ancestry in the war can be found in the Americans of Japanese Ancestry sub-subseries within the Racial Groups subseries. Researchers can also find more information on the 442nd Infantry Regiment and 100th Infantry Battalion at the University of Hawaii archives in the Japanese American Veterans Collection.