Honouliuli National Monument is located on land that, during World War II, served as the largest and longest-used confinement site for Japanese Americans, European Americans, and resident aliens in Hawai'i.
Run by the U.S. Army and opened in March 1943, Honouliuli was both a civilian internment camp and a prisoner of war camp with a population of approximately 400 internees and 4,000 prisoners of war over the course of its use. The 160 acre internment camp contained 175 buildings, 14 guard towers, and over 400 tents. Internees referred to Honouliuli as Jigoku-Dani ("Hell Valley") because its secluded location in a deep gulch trapped heat and moisture and reinforced the internees' sense of isolation and unjust imprisonment.
The majority of Honouliuli's civilian internees were American citizens predominantly Japanese Americans who were citizens by birth suspected of disloyalty. They included community, business, and religious leaders. The remaining group comprised predominantly German Americans, though there were also Americans and aliens of Italian, Irish, Russian, and Scandinavian descent.
As a prisoner of war camp, Honouliuli held enemy soldiers and labor conscripts from Japan, Korea, Okinawa, Taiwan, and Italy. Honouliuli also held women and children who were Japanese civilians displaced from the Pacific. Honouliuli closed in 1946 and was soon forgotten as Americans celebrated the victories of World War II. Fast-growing vegetation quickly took over the site. At present, there are no NPS facilities on site.