Kittanning Gap, a wooded ravine on the Allegheny Front west of Altoona, was once an important passage through the escarpment in central Pennsylvania. Formed by seasonal freshets rather than a large stream, it has gentler slopes than many nearby gaps, making it better suited to ox carts, wagons, and other animal-drawn vehicles than steeper valley routes. In the 18th century it served as one option along the Kittanning Path, a Native American trail later used as an emigrant road. As westward migration grew from the 1780s to the 1830s, such easier grades mattered, and the same corridor later influenced the railroad approach that led to Horseshoe Curve.