Tionesta Dam impounds the largest reservoir lake in the county, with a purpose of flood control. Where not cut by the narrow valleys of these rivers, the land is rolling. Forest County has public forest lands in various categories including portions of Allegheny National Forest, Cook Forest State Park, State Game Lands 24, and Cornplanter State Forest. Additional lands are owned by the U.S. Army Corps of Engineers. Most of the public lands, and much of the private lands, are in forested woodlands.
Additional acreage is in abandoned or semi-managed farmlands.
Commercial agriculture acreage comprises a relatively small part of the county. Most of the active farms are located in the southeastern part of the county, and concentrate on dairy and forage production. The county was formed in 1848, and Tionesta is the county seat. The main non-agricultural industries are forest production and services, often related to tourism. One of Pennsylvania's seven completely rural counties, Forest is also one of the most sparsely populated.