The Marshall Site in Illinois is a rare Native American rock art site centered on a granite boulder on a wooded hillside above the eastern bank of the Illinois River, across from Chillicothe. Five petroglyphs were carved into the boulder’s top face in thin incised lines: three human-like figures, an L-shaped form thought to represent a weapon, and a possible bird-like figure. Archaeologists believe the carvings date to the historic period between 1673 and 1835, when Native villages, including Potawatomi and Kickapoo communities, were nearby in the Illinois River valley. Discovered in 2011, the site was added to the National Register of Historic Places in 2014 for its rarity and importance.