Fall line is a series of waterfalls and rapids formed where hard rock meets softer rock. The falls and rapids develop as erosion by a river or stream wears away some of the softer rock, creating a ledge over which the water flows. In the Eastern United States, a Fall Line stretches from southern New York to Alabama. It formed as water carried away some of the soft sediments of the Atlantic Coastal Plain, leaving behind the harder rocks of the Piedmont—the plateau east of the Appalachian Mountains. Nearly every stream on the Fall Line has rapids or waterfalls.
The Fall Line of the Eastern United States is a great source of electric power. The falling water can be used to turn turbines to generate electricity. Also, the Fall Line generally marks the farthest point inland a ship can go. For these reasons, many important cities are found along the Fall Line.
See also Piedmont Region; Plain; Waterfall.
