Ridge-and-Valley Appalachians
The Ridge-and-Valley Appalachians are a long, wavy belt of mountains in the eastern United States. They lie between the Blue Ridge to the east and the Appalachian Plateau to the west, forming a broad arc from New York to Alabama. The area is divided into three parts: the Hudson Valley, the Central region, and the Tennessee section.
People have lived in the river valleys for thousands of years. The Cherokee had towns along many rivers in western South Carolina and western North Carolina, and in present-day Tennessee on the western side of the mountains. The Catawba lived along the upper Catawba River in western North Carolina.
The ridges and valleys made east–west travel difficult. Early European settlers found it hard to move west toward the Ohio Country, the Northwest Territory, and Oregon Country. Crossing the middle of the range was nearly impossible, so they used passes like Cumberland Gap, Braddock’s Road, and Forbes Road. These later became early national roads, such as Wilderness Road and Cumberland Road, and later U.S. Route 40 and U.S. Route 30. Rivers were the main transportation routes for the Ohio Country, and building railroads and modern highways here was challenging in the 19th and 20th centuries.
Geographically, the eastern end of the region is the Great Appalachian Valley, just west of the Blue Ridge. The western edge has steep cliffs like the Allegheny Front, the Cumberland Mountains, and Walden Ridge. The Ridge-and-Valley Province sits on the west side of the Blue Ridge and runs from southeastern New York through New Jersey, Pennsylvania, Maryland, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama.
The ridges are long and even, with long, continuous valleys in between. The rocks in the area were folded and deformed during the Alleghanian orogeny, about 325 to 260 million years ago. Softer rocks such as shale and limestone eroded to form the valleys, while harder rocks like quartzite formed the ridges. The ridges mark the edges of tougher rocks; the valleys show where softer rocks were removed. Smaller streams followed the lines of the weaker rocks, cutting their own valleys.
Some large rivers—the Delaware, Susquehanna, New River, and Potomac—are older than the mountains and cut water gaps through the hard ridges. The landscape shows signs of being worn down to a low relief and then slowly uplifted, allowing rivers to maintain their courses while cutting through the ridges. Valleys can be synclinal or anticlinal, and the region’s development in central Pennsylvania is sometimes called the Pennsylvania climax.
This page was last edited on 3 February 2026, at 12:15 (CET).