After the war, the site became the first home of Argonne National Laboratory, a federally funded research and development center.

While buried remnants remain, substantial remediation has occurred at the site and it has been certified safe for ordinary public access by Illinois and the EPA since the late 1980s.

It was desired that the site be within commutable distance of Chicago, but for reasons of safety and security, should not be too close to the city.

[1] During a horseback ride in early 1942, the head of the Metallurgical Project, Professor Arthur Compton, identified a suitable site in what was then known as the Argonne Forest[2] Once an estimate of the required land was available, the way was clear for the U.S. Army Corps of Engineers to lease 1,025 acres (4.15 km2) of land from the forest preserve district, which was done in August, 1942.

Shortly after the December 1942 demonstration of the first self-sustaining chain reaction at the University of Chicago, the research group led by Enrico Fermi needed to move to the larger, more remote laboratory campus.

[3] Surveillance of the site since the demolition in the 1950s has found small amounts of soil contamination with uranium and fission products, and some wells in Red Gate Woods had tritium concentrations as high as 13 nCi/L (480 Bq/L) in the late 1970s.

[3] In April 1998 the fence separating Site A from the rest of Red Gate Woods was taken down after a DOE determination that the risk to the public while enjoying the forest preserve is minimal.