This legislation directs the Secretary of the Interior to undertake a special resource study of significant archaeological sites in Illinois, specifically the Cahokia Mounds State Historic Site, Emerald Mounds, and Pulcher Mounds. These sites are recognized as crucial remnants of the ancient Mississippian culture, which was a prominent prehistoric civilization in North America. The primary objectives of this study are to evaluate the national significance of these mounds and to assess their suitability and feasibility for potential designation as a unit of the National Park System. Furthermore, the Secretary must explore various other alternatives for the preservation, protection, and interpretation of these sites, involving federal, state, local, private, and nonprofit organizations. The study mandates consultation with interested governmental entities, private organizations, and individuals, and requires identifying detailed cost estimates for any federal acquisition, development, interpretation, operation, and maintenance associated with the considered preservation alternatives. A comprehensive report detailing the study's findings, conclusions, and recommendations must be submitted to Congress within three years of funding availability.