The 111-acre Piney Creek Ravine Nature Preserve in southwestern Illinois contains the highest frequency of prehistoric rock-art sites per acre of any area documented in the state. A 1997 partial archaeological survey of the preserve recorded four such sites and two prehistoric rockshelter sites. The Piney Creek site (11R26) is the largest documented prehistoric rock-art site in the state, with over 150 carved and painted designs. These designs are documented through a combination of photographs and tracings on clear acetate. Stylistic design differences suggest they are not all contemporaneous. The prevalence of winged anthropomorphic and zoomorphic figures, and the presence of horned/eared anthropomorphs—one of which holds three spears, suggests some of the designs were created as part of shamanistic ceremonies. The designs appear to date to Late Woodland and Mississippian times (ca. A.D. 450–1500). Excavation of a test square in the shelter floor revealed Archaic, Crab Orchard, L