The Appalachian Mountains were a significant barrier to westward expansion during the Colonial period.

During the colonial era, the rugged terrain and dense forests of the Appalachian Mountains presented considerable challenges for settlers moving westward from the coastal colonies. The mountains created a natural barrier that limited access to the vast lands beyond, making travel and trade difficult. This led to tensions between colonial settlers and Native American tribes, as well as conflicts over land ownership. The eventual exploration and gradual settlement of the region occurred more extensively after the American Revolutionary War, but during the colonial period, the Appalachians played a crucial role in shaping the patterns of settlement and expansion in the early United States.