The Cumberland Gap is a natural passage through the Appalachian Mountains that historically marked the boundary between the Appalachian Highlands and the Great Valley.

The Cumberland Gap, a pass through the Appalachian Mountains, serves as a natural route between the Appalachian Highlands to the east and the Great Valley to the west. This gap played a significant role in American history, particularly during the westward expansion in the 18th and 19th centuries, as it was used by settlers moving into the western territories. The pass is located at the intersection of Kentucky, Tennessee, and Virginia, and it continues to be an important historical and geographical feature in the Appalachian region.