Anders Run Natural Area is a 96 acre protected area in Warren County, Pennsylvania, United States. It is part of Cornplanter State Forest. The Natural Area contains about 50 acre of old-growth forest. Although parts of the area were logged during the first two decades of the 19th century, tree rings of fallen trees have revealed 200-year-old white pines and 400-year-old hemlocks. These trees are also known for their impressive size. In addition to its forests, the Natural Area also has a stream with native trout and fine stands of wildflowers. There is a historic residence on the property built in 1841 called the "Little Stone House", though in recent years the structure has fallen into a severe state of disrepair. The Natural Area has about 2 mi of hiking trails.