Allegheny National Forest, National forest in northwestern Pennsylvania, United States

Allegheny National Forest covers 513,175 acres of the Allegheny Plateau in northwestern Pennsylvania, about 100 miles northeast of Pittsburgh. Its woods are dominated by black cherry, maple and other hardwoods, with eastern hemlock and American beech; the Allegheny River is impounded by Kinzua Dam to form Allegheny Reservoir. Streams such as the one in the photograph run shallow and clear over olive-green and brown stones, lined with grass and slender trees.

The area became a national forest in 1923 from heavily logged land where timber operations dominated during the 19th century. After being designated, the woodland gradually recovered and has regrown since then.

Before European settlement, Native Americans burned patches of understory to boost berry and oak mast production, aid hunting and ease travel. This burning shaped the open woodland structure the first settlers found. The forest's name comes from the Allegheny River, itself from a Lenape word. The Seneca Nation holds treaty rights in the region and maintains a presence near Kinzua Dam.

The forest headquarters is in Warren, with ranger stations in Marienville (Forest County) and Bradford (McKean County). The forest lies about 100 miles northeast of Pittsburgh. Camping, boating, picnicking, hiking and viewing facilities line the Allegheny Reservoir, built up since Kinzua Dam was completed in 1965. Two designated wilderness areas, Hickory Creek and Allegheny Islands, have no permanent settlements.

Beneath the forest lies a significant oil region, and crude oil production occurs within the area, controlled through private mineral rights. This simultaneous use of resource extraction and conservation shows an unusual arrangement for a wooded region.