The Appalachian Mountains serve as the natural feature that separates the Coastal Plain from inland regions in the eastern United States.

Stretching from Alabama to Canada, this mountain range forms a significant geographical boundary, influencing the climate and ecosystems on either side. The Coastal Plain, characterized by its flat terrain and low elevation, lies to the southeast of the Appalachians, while the rugged, elevated landscapes of the Appalachian Mountains rise to the northwest. This division creates distinct environmental conditions, leading to diverse flora and fauna. Additionally, the Appalachian Mountains play a vital role in shaping weather patterns and water drainage in the region. Their presence not only impacts geography but also contributes to the cultural and economic differences between the Coastal Plain and the inland areas.