Tussey Mountain is a long, narrow ridge in central Pennsylvania that extends from near the Mason–Dixon line north toward the Seven Mountains, separating several valleys and shaping the region’s waterways and travel routes. Streams and rivers cut through it at multiple gaps and water passages, creating corridors later used by roads and railroads, including the route through The Narrows at Everett. Geologically, it is part of the Ridge and Valley Appalachians, formed from folded Paleozoic rock and erosion that left its distinctive double-crested shape. Today it serves as a wildlife corridor, bird migration route, recreation landscape, and a longstanding landmark in daily travel across the region.