Advances in American bottom prehistory: Illinois transportation archaeology two decades after I-270

In 1956 the Illinois Department of Transportation (IDOT) issued its first directive indicating to its engineers that "ruins having historical value should not be needlessly destroyed." Fifty years later IDOT's cultural resources program continues to be one of the best in the nation. In this article we detail the history of IDOT's cultural resources efforts and focus on its role in carrying out one of the premier CRM projects in the Eastern Woodlands - The FAI-270 Archaeological Mitigation Project. We especially stress the ongoing nature of IDOT's archaeological program and its importance in expanding our knowledge of American Bottom prehistory.