Known as the Gate House, this checking station was constructed in the post World War Two years and was operated by the United States Atomic Energy Commission to control access to the K-25 Gaseous Diffusion Plant from 1949 to 1953. Although the city of Oak Ridge opened to the public on March 19, 1949, access to the K-25 Gaseous Diffusion Plant remained restricted. Built with concrete and bullet-proof windows, it reflects the heightened security conditions of the early Cold War years. Two other identical checking stations controlled access to the Y-12 Plant at Bear Creek and the X-10 Graphite Reactor on Bethel Valley Road. Virtually unchanged since their time in operation, all three checking stations were added to the National Register of Historic Places in 1992.