Lusk Creek Canyon is a 906-acre gorge in the Lusk Creek Wilderness Area of the Shawnee National Forest in southern Illinois, formed where erosion carved deeply into Pennsylvanian sandstone around a broad horseshoe bend in Lusk Creek. Beyond its striking canyon landforms, it has unusual ecological importance for the region, supporting fan-leafed clubmoss, cinnamon fern, royal fern, and ten endangered or threatened plant species. Because of its distinctive sandstone landscape and preserved biological diversity, the canyon was designated a National Natural Landmark in 1980.