It is rolling hill country that gently rises to 1,000 feet, then doubles that height at the foothills of the Blue Ridge Mountains, where its topography becomes more rugged. The Piedmont is Virginia’s largest region. The “Fall Line” runs through the port cities of Alexandria, Fredericksburg, Richmond, and Petersburg west of those points, the rivers are too shallow for deep-bottom ships to navigate. Those rivers give the state its unique geography that has strongly affected its history and economy.
Virginia’s Piedmont is separated from its Coastal Plain by a “Fall Line,” where rivers, small waterfalls, and rapids cascade or “fall” off hard, resistant rocks as they make their way to the ocean. “Piedmont” is a French word meaning “foot of the mountains.” The American Piedmont extends from Pennsylvania to Alabama. When the ice sheets melted, 5,000–6,000 years ago, the Chesapeake lowland filled to form a bay, and the Coastal Plain slowly uplifted. During the last Ice Age, 25,000 years ago, sea levels were dramatically low and the Coastal Plain extended far eastward-fifty miles or more than it does today. When sea levels rose and fell with the repeated melting and growth of large continental glaciers, this plain was alternately submerged and exposed. The surface is covered by a thick wedge of eroded clay, sand, and gravel-two thirds of which was carried eastward by Virginia’s many rivers. At its core is a solid rock foundation formed 250–500 million years ago.
As with all of the Virginia regions, its Coastal Plain was sculpted by hundreds of millions of years of geological evolution. A low-lying Coastal Plain spans the eastern seaboard of the United States from New Jersey to Georgia, extending westward from the ocean to a point where the flatness of the landscape ends in Virginia the terrain rises 300 feet above sea level.
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