The Poston Internment Camp, located in Yuma County (now in La Paz County) in southwestern Arizona, was the largest (in terms of area) of the ten American concentration camps operated by the War Relocation Authority during World War II. The site was composed of three separate camps arranged in a chain from north to south at a distance of three miles from each other. Internees named the camps Roasten, Toastin, and Dustin, based on their desert locations. The Colorado River was approximately 3 miles (4.8 km) to the west, outside of the camp perimeter.