With more than 10,000 years of human occupation and thousands of recorded archeological sites in a 4,000 square mile area, the region surrounding the confluence of the Mississippi River and the Illinois River has often been referred to as the "Nile of North America". This predominately rural landscape is home to the Center for American Archeology, located in Kampsville, Illinois. Originally formed in 1953, the CAA's mission is to discover and disseminate the unwritten story of earlier Americans' lifeways, accomplishments, and changing natural environment. Through integrated programs of archeological investigation, educational outreach and cultural stewardship, the CAA strives to accomplish this mission.

From 1968-1979, the CAA and Northwestern University conducted investigations at the Koster Site in Greene County, Illinois. This location was home to many communities over 10,000 years of human occupation recorded at the site, with at least 26 separate living horizons defined. Major villages were present at Koster ca. 3300, 5000, and 6600 BC. Archeologists found evidence of the earliest house structures in North America, one of the earliest domesticated dog burials in the new world (5000 BC), millions of artifacts, and evidence of extensive trade networks that stretched from the Great Lakes to the Gulf of Mexico. The Koster site set the standard for multidisciplinary archeological investigation, and reshaped how archeologists have come to understand the lifeways of the prehistoric peoples of North America. Thousands of professional and avocational archeologists worldwide consider their time spent in a Koster Site field school to be a formative experience.