The quartzite spires of Seneca Rocks, which tower 900 feet above the North Fork of the South Branch of the Potomac River, are but one of a series of rock "fins" exposed along the River Knobs, a jagged ridgeline running parallel to North Fork Mountain to the east. Nelson Rocks, Champe Rocks and Judy Rocks are other examples of crags rising from the same ridgeline. These exposed rock structures are part of a much larger geological formation: an arch-like fold of stratified rock layers referred to as the Wills Mountain anticline, which formed about 200 million years ago at the end of the Paleozoic Era. For geology buffs, this video explains it all.
Seneca Rocks is protected as part of the Spruce Knob-Seneca Rocks National Recreation Area (NRA) in the Monongahela National Forest. In addition to the NRA's fantastic natural history, which draws hordes of climbers and hikers from across the eastern US, the area has a rich human history. The Sites Homestead, contructed by Jacob Sites in 1839, is preserved by the Seneca Rocks Disovery Center, which itself is located adjacent to a Native American camp site along Seneca Creek. A strenuous hiking trail leads to an overlook at the top of Seneca Rocks, with breathtaking views of the Allegheny Front to the west. The extensive moss and lichen-encrusted boulder fields at the base of Seneca Rocks are equally stunning and give a real sense of the primordial orgins of the underlying bedrock.