Piedmont, geographic region in the eastern United States, running some 600 miles (950 km) between New Jersey (north) and Alabama (south) and lying between the Appalachian Mountains (west) and the Atlantic Coastal Plain (east). It comprises a relatively low rolling plateau (from 300 to 1,800 feet [90 to 550 metres]) cut by many rivers and is a fertile agricultural region. Cotton is the most important crop in the southern areas, while tobacco and fruit predominate in the north.