Compton selected a site in the Argonne Forest, part of the Forest Preserve District of Cook County, about southwest of Chicago. The full-scale production facilities would be co-located with other Manhattan Project facilities at a still more remote location in Tennessee. Some of land was leased from Cook County for the pilot facilities, while an site for the production facilities was selected at Oak Ridge, Tennessee. By the S-1 Executive Committee meeting on September 13 and 14, it had become apparent that the pilot facilities would be too extensive for the Argonne site, so instead a research reactor would be built at Argonne, while the plutonium pilot facilities (a ) would be built at the Clinton Engineer Works in Tennessee.