Tiadaghton State Forest is a Pennsylvania State Forest (Forest District #12) in the Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry. The forest is primarily in western and southern Lycoming County, with small portions in Clinton, Potter, Tioga, and Union Counties. The district's topography consists of narrow, flat to sloping plateaus cut by deep, steep-sloped valleys carved by fast moving mountain streams, including Pine Creek, Slate Run, and their tributaries. The Tiadaghton district extends south across the lowland along the west branch of the Susquehanna River to the narrow crests of Bald Eagle Mountain and North and South White Deer Ridge. The majority of forest cover is dominated by mixed oak forests, with some areas of northern hardwoods. The Tiadaghton State Forest is one of eight forest districts in the Pennsylvania Wilds region.