Anders Run Natural Area is a 96-acre protected tract in northwestern Pennsylvania within Cornplanter State Forest, valued especially for preserving about 50 acres of old-growth forest. Although parts were logged in the early 19th century, the surviving woods include notably old and large white pines and eastern hemlocks, with tree-ring studies showing some pines around 200 years old and hemlocks about 400 years old. The area also contains a trout stream, wildflower patches, and the Little Stone House, built in 1841 and now in severe disrepair. About 2 miles of hiking trails run through this protected landscape.