High Quality Content by WIKIPEDIA articles! Buffalo Rock State Park & Effigy Tumuli is an Illinois state park on 298 acres (121 ha) in LaSalle County, Illinois, USA. The park is located in LaSalle County next to Starved Rock State Park, and was once used as a "blind canyon" for Indians to capture buffalo. Effigy Tumuli consists of five earth art animal sculptures native to the Illinois River was constructed as a tribute to Native American tradition. This 298 acre park is located 3 miles west of Ottawa, Illinois, and approximately 85 miles southwest of Chicago, Illinois. Now, this sandstone bluff carved by the Illinois River during the Pleistocene epoch, serves as a State Park for local residents and tourists.