This site was managed before the war by the federal Bureau of Reclamation for a major irrigation project. Construction of the 650 military-style barracks and surrounding guard towers began in June 1942, and the camp opened on August 11, when the first Japanese Americans arrived by train from the Pomona, Santa Anita, and Portland assembly centers. The camp would hold a total of 13,997 Japanese Americans over the next three years, with a peak population of 10,767, making it the third-largest "town" in Wyoming before it closed on November 10, 1945.