: The bedrock is primarily sandstone and quartzite, which are extremely resistant to weathering. Outdoor Recreation & Rail Trails

: An 17.6-mile trek through history featuring two dark, damp, and abandoned tunnels (Sideling Hill and Ray's Hill) left behind when the highway was rerouted.

: The range has been home to humans for thousands of years, from the indigenous Monongahela and Shawnee to the Scotch-Irish and German immigrants who braved the "western waters" in the 1700s. Expand map Industrial History Scenic Peaks & Wilds Rivers & Trails Pennsylvania Turnpike Abandoned Tunnels

: A sharp, massive escarpment that serves as the Eastern Continental Divide , separating the Mississippi River and Chesapeake Bay watersheds.

The mountains have shaped American industry and transportation:

The range is defined by its dramatic topography and unique ecosystems:

The Alleghenies are a hub for hiking and cycling, often utilizing abandoned railroad corridors that once breached the mountain barrier: