The Appalachian Mountains, often called the Appalachians, are a
vast system of mountains in eastern North America. The Appalachians
are believed to have been the highest mountains on earth roughly 460
million years ago during the Ordovician Period, much like (but
higher than) the Himalayas today, when all of today's continents
were joined as the supercontinent Pangaea.
Appalachian chain is a barrier to east-west travel as it forms a
series of alternating ridgelines and valleys oriented in opposition
to any road running east-west.
Definitions vary on the precise boundaries of the Appalachians. The United States Geological Survey (USGS) defines the Appalachian
Highlands physiographic division as consisting of thirteen
provinces: the Atlantic Coast Uplands, Eastern Newfoundland
Atlantic, Maritime Acadian Highlands, Maritime Plain, Notre Dame And Megantic Mountains, Western Newfoundland Mountains, Piedmont, Blue
Ridge, Valley and Ridge, Saint Lawrence Valley, Appalachian
Plateaus, New England province, and the Adirondack provinces.
A common variant definition does not include the Adirondack
Mountains, which are often said to have more in common with the
Canadian Shield than the Appalachians.
- Chief summits
- Influence on history