Allegheny Mountains

Allegheny Mountains or Alleghenies, complex of ranges and uplands of the Appalachian system. The name is usually applied to the ranges west of the Blue Ridge in Pennsylvania, Maryland, Virginia, and West Virginia. The mountains form a divide between rivers draining into the Gulf of Mexico and those flowing into the Atlantic Ocean. The height varies from 610 m (2000 ft) to a high point of 1,482 m (4,861 ft) at Spruce Knob in West Virginia. The range is composed of stratified rocks of the Silurian, Devonian, and Carboniferous ages and is rich in minerals, especially coal, which is important to the regional economy. The mountains are heavily forested, and the timber industry also is important to the economy of the Allegheny region. The mountains formed a natural barrier to communication and transportation during the colonial period and the early years of nationhood, but roads and railroads now cross the range.