Appalachian Mountains
or Appalachians,
great mountain system of E North America, nearly parallel with the Atlantic coast, and extending from the province of Québec in Canada to N Alabama. The system is about 2400 km (about 1500 mi) long and varies from about 160 to more than 480 km (about 100 to more than 300 mi) in width. Its altitude varies between about 460 and nearly 2130 m (about 1500 and nearly 7000 ft). The three divisions of the system--N, central, S--vary considerably in geologic age, having been raised by a series of crustal plate collisions that began during the Ordovician period and climaxed in the Permian . The N division--including the Green Mountains and the White Mountains, the highlands of Maine, the Shickshock Mts., and the Notre Dame Mts. of Québec--terminates in the hills of Newfoundland. The chief ranges of the central section are the Catskill Mountains, Allegheny Mountains or Alleghenies, and Blue Ridge or Blue Ridge Mountains. The Blue Ridge range is the principal uplift of the Appalachians. This range rises from the Piedmont Plateau to heights far greater than the Alleghenies attain. Beginning prominently in South Mt. in Pennsylvania, it stretches SW in greater and greater heights, through Virginia and W North Carolina, where it divides, the N branch continuing W to Georgia as the Great Smoky Mountains. This range, a broad mass of mountains on the border between North Carolina and Tennessee, contains peaks higher than those of the White Mts. of New Hampshire. The culminating group of the Blue Ridge is known as the Black Mountains. The highest peak of the Appalachians, Mt. Mitchell (2037 m/6684 ft), and many peaks above 1829 m (6000 ft) in height are situated in this group. The principal range of the S Appalachians, which extend S into Alabama from the New R. valley in Virginia and West Virginia, is the Cumberland Plateau and Cumberland Mountains. Elevations in this range average about 610 m (about 2000 ft).
The Appalachian Mts. are heavily forested and contain deposits of iron ore, anthracite, bituminous coal, zinc, slate, limestone, asbestos, mica, granite, and emery. Along the W slope from SW New York through W Pennsylvania, into West Virginia, Kentucky, and Tennessee, lie coalfields.
Numerous rivers make their way through the Appalachians. Among the more important are the Connecticut, Hudson, Delaware, Schuylkill, Susquehanna, Potomac, James, and Rappahannock (flowing E or SE) and the Cumberland, Kanawha, Allegheny, Monongahela, Tennessee, and others (flowing toward the W).