The Shawnee Hills Wine Trail wanders along winding scenic roads and rolling hills on the Western side of the Shawnee National Forest. It will bring you to unique small towns, outdoor adventures among sandstone bluffs, and surprising history. Shawnee Hills is the only Federally designated wine grape growing region in Illinois because of how it's special soil and climate affect the grapes.
Kerr Canyon is one of the historic sites along this wine trail. Deep in the canyon is the site of one of eleven stone forts in Southern Illinois. There are signs that prehistoric people lived in shelter caves in the bluffs. Unfortunately in the mid 20th century it was heavily dug for artifacts by amateur archeologists and can now be visited only with owner permission. The good news is that pictures and artifacts of the site are on display in the Union County Museum in Cobden, one of the unique small towns along the wine trail. AND another of the stoneforts can be visited at nearby Giant City State Park.
The cache is not in the canyon. It is conveniently along the road.