The Appalachian region was formed close to 480 million years ago.
The Northern Appalachian region ranges from Hudson River to Newfoundland and Labrador; it is scattered elevations mostly around Quebec
The Central Appalachians range from Hudson Valley to New River and is mostly flat due to the fact that is runs through New York and New Jersey Highlands.
The Southern Appalachians runs from New River and onwards.
The Appalachian Mountains were formed due to multiple collisions of tectonic plates and carried through the Mesozoic and Paleozoic Eras. The Appalachian Mountains have actually changed the area of continents because when measured last the continents were in a different place then before The Appalachian Mountains were formed.
“The Appalachians are among the oldest mountains on Earth, born of powerful upheavals within the terrestrial” –Britannica online encyclopedia.