Add to ORKGBibliography: pages 92-97.Documented effigy mound complexes in the northern two tiers of Illinois counties of the Effigy Mound region are described and discussed. Mound number, form, distribution, previous investigation, and recent effigy survey are covered in the study. Current findings indicate that 88% of recorded Illinois effigy mounds have been destroyed. This figure supports rates of destruction recently calculated for Iowa and Wisconsin mounds. Suggestions are made for preservation of remaining mounds. Analysis of several variables indicates distribution patterns of Illinois sites correlate with those determined for adjacent states. Complexes tend to be associated with major waterways. They often occur in groups or clusters along riv...