Giant City Stone Fort Site in Giant City State Park is a prehistoric Late Woodland stone enclosure in southern Illinois, dating to about AD 600 to 900. One of ten similar enclosures identified in Southern Illinois, it occupies prominent high ground on a sloped ridge. Although once thought defensive, such sites are now generally interpreted as gathering places or ceremonial sites, with their exact purpose still uncertain. European settlers dismantled the original wall for building stone, leaving only its base. The Civilian Conservation Corps reconstructed the wall in 1934, and archaeological study beginning in 1956 led to surveys before the site was listed on the National Register of Historic Places in 2002.