What stretches about 1200 miles and borders the Blue Ridge Mountains?
Great Appalachian Valley The Great Valley, also called the Great Appalachian Valley or Great Valley Region, is one of the major landform features of eastern North America. It is a gigantic trough—a chain of valley lowlands—and the central feature of the Appalachian Mountain system. The trough stretches about 1200 mi from Quebec to Alabama and has been an important north-south route of travel since prehistoric times.
Saddle Mountains The Saddle Mountains consists of an upfolded anticline ridge of basalt in Grant County of central Washington state. The ridge, reaching to 2,700 feet, terminates in the east south of Othello, Washington near the foot of the Drumheller Channels. It continues to the west where it is broken at Sentinel Gap (a water gap through which the Columbia River passes) before ending in the foothills of the Cascade Mountains.