Hell Gap in eastern Wyoming preserves an exceptionally clear, deeply layered record of human activity on the Great Plains from about 13,500 to 7,600 years before present. Discovered in 1959, the site has yielded artifacts and features from Clovis, Folsom, Agate Basin, Alberta, Midland, Cody, Lusk, and Hell Gap traditions, and helped define the Hell Gap, Goshen (Plainview), and Frederick complexes. Its well-preserved deposits have been crucial for tracing cultural transitions and daily life, including faunal remains, fireplaces, and posthole circles interpreted as domestic structures more than 12,000 years old, among the oldest known in North America.