|Appalachian Mountains or Appalachians|
|a mountain system of E North America, extending from Quebec province in Canada to central Alabama in the US: contains rich deposits of anthracite, bitumen, and iron ore. Highest peak: Mount Mitchell, 2038 m (6684 ft)|
|Appalachians or Appalachians|
Note: Location of the Appalachian Trail, the world's longest continuous hiking path. It extends over two thousand miles from Maine to Georgia.
Note: Historically, the Appalachian Mountains were a barrier to early western expansion. In the early 1840s, railroads began to transport settlers across the mountains, permitting access to the frontier.