Today, the Honouliuli National Historic Site is located near Waipahu on the island of Oahu, in the state of Hawaii in the U.S. During WWII, from 1943 until it closed in 1946, the Honouliuli Internment Camp was located there, It initially held 320 internees but also became the largest and longest-operating prisoners of war camp for nearly 4,000 individuals.

Of the 17 sites that were associated with the history of internment on the various Hawaiian islands during WWII, this camp was the only one built specifically for prolonged detention.

The camp was constructed on 160 acres (0.65 km2) of land with an 8-foot (2.4 m) dual barbed-wire fence enclosing the camp and a company of military police who stood guard from its 8 watchtowers. The isolated location in a deep gulch led Japanese American internees to nickname it “hell valley”.

The camp was further divided by barbed wire into sections, intended to separate internees by gender, nationality, and military or civilian status. By August 1943, there were 160 Japanese Americans and 69 Japanese interned there, according to a military colonel representative from the Swedish Legation who inspected the camp under the Geneva Convention.

Eventually the camp held more than 4,000 Okinawans, Italians, German Americans, Koreans and Taiwanese as well. Notable internees included two legislators for the Territory of Hawaii.

Repatriation efforts began in December 1945 and continued into 1946.

More Info: en.m.wikipedia.org