Answer:
The upland area that lies to the west of the mountain range in the eastern United States is the Appalachian Plateau.
Explanation:
The Appalachian Plateau is a region of <em>flat and wide</em> land that is fairly <em>high </em>above sea level. It lies to the <em>west</em> of the Appalachians and it stretches from the north (<em>Adirondack Mountains</em> in the state of New York) to the <em>Gulf Coastal Plain</em> in the south.
The Appalachian Plateau has a massive extension:
- Adirondacks, New York
- Pennsylvania
- West Virginia
- Ohio
- Kentucky
- Virginia
- Tennessee
- Alabama
- Gulf Coastal Plain
The western and eastern areas of the plateau are bordered by a series of <em>mountain ranges</em>, one of them being the Appalachian Mountain Range.
The Appalachian Mountain Range runs all along the eastern United States, and in terms of geology, it is the oldest range in North America. <em>Mount Mitchell</em>, being its highest <em>peak</em> (6,684 ft) is located in <em>North Carolina</em>.