PS Knoll Lookout Complex is a historic fire lookout in eastern Arizona's Apache-Sitgreaves National Forest, occupying a nine-acre site at 8,045 feet. Built in the mid-1930s, its steel tower was constructed in 1933 by the Aermotor Windmill Company, known for standardized lookout designs, and rises 45.9 feet above the ground to provide broad views over the surrounding forest. The complex also includes a house, storage shed, and outhouse, preserving the essential working layout of a remote forest fire detection station. Together, these features reflect the important role staffed lookouts played in monitoring wildfires in the early twentieth-century American West.