Fort Yellowstone, established in 1891 at Mammoth Hot Springs, served as a U.S. Army post responsible for managing Yellowstone National Park until the National Park Service took over in 1918. Between 1891 and 1913, 60 buildings were constructed—first in wood “cottage style” and later in locally quarried sandstone—and many of these historic structures now house park offices, staff residences, and visitor facilities. Learn more from the Wyoming Veteran’s Memorial Museum.