Lewistown Air Force Station came into existence as part of Phase III of the Air Defense Command Mobile Radar program. On October 20, 1953 ADC requested a third phase of twenty-five radar sites be constructed. On 31 July 1963, the site was redesignated as NORAD ID Z-25, and the AN/FPS-3A was removed in 1963, replaced by an AN/FPS-66 search set. This radar was upgraded to an AN/FPS-66A in 1966. The AN/FPS-90 was removed from service in 1968.