CUMBERLAND PLATEAU

westernmost of three divisions of the Appalachian Mountains, U.S., extending southwestward for 450 miles (725 km) from southern West Virginia to northern Alabama. The plateau is 40 to 50 miles (65 to 80 km) wide and lies between the Appalachian Ridge and Valley region to the east and the rolling plains to the west. It merges with the Allegheny Plateau on the north and with the Gulf Coastal Plain on the south. The region is dissected mainly by headstreams of the Cumberland and Kentucky rivers and by tributaries of the Tennessee River, the valley of which in northern Alabama holds Tennessee Valley Authority reservoirs. Other notable features on the plateau include the Cumberland, Pine, Lookout, and Sand mountains, Cumberland Gap, and Walden Ridge. The roughest and highest portion of the plateau is a narrow linear ridge about 140 miles (225 km) long that forms its eastern margin in eastern Kentucky and northeastern Tennessee; the name Cumberland Mountains is generally applied to this area. These mountains vary in elevation from 2,000 feet (600 m) to 4,145 feet (1,263 m) at Big Black Mountain, the highest point in Kentucky. The plateau is underlain by large deposits of coal, limestones used for cement, and fine-grained sandstones suitable for construction and decorative purposes. The region is well-covered by hardwood trees, which constitute a major resource and are concentrated in the Daniel Boone and part of the Jefferson national forests in Kentucky. The rough topography, especially in Kentucky and Tennessee portions, has resulted in isolated settlements and local economies based on subsistence agriculture. Much of the plateau's history centres on the Cumberland Gap (now a national historical park), which provided westward passage for the early settlers and was of strategic importance in the American Civil War.