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What is the Great Appalachian Valley?

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Blue Ridge, Appalachian Mountains — Appalachian Mountains Blue Ridge, part of the Appalachian Mountains.

The Great Appalachian Valley is a long, continuous chain of valley lowlands that forms a major part of the Appalachian mountain system in North America. Extending from Canada in the northeast to Alabama in the southwest, this extraordinary trench of shale and limestone serves as a vital lowland passage and has been a primary route through the mountains since pioneer times.12

The valley encompasses several distinct regional valleys, including the St. Lawrence River valley in Canada, as well as the Kittatinny, Cumberland, Shenandoah, and Tennessee river valleys in the United States. Geologically, it is characterized by sedimentary rocks and is known for its rich farmland and numerous caverns formed by the erosion of limestone. In its southern reaches, the valley divides the Appalachian Mountains into two subequal portions, while in the north, it separates the Appalachian ranges from the Adirondack group.134