Great Falls of the Potomac

Just 15 miles (24 km) upstream of the nation's capital, the Potomac River throws itself over a jumble of jagged rock and drops 76 feet (23 m) in less than a mile. Great Falls is not one curtain of water but a series of falls of about 20 feet (6 m) each, after which the river squeezes from nearly 1,000 feet (300 m) wide to between 60 and 100 feet (18 to 30 m) as it races through Mather Gorge. The site marks the fall line, where the hard rocks of the Piedmont give way to the soft sediments of the Atlantic Coastal Plain.

The falls blocked river traffic, and George Washington set out to beat them. His Patowmack Company, founded in 1785, spent 17 years building a 1,820-yard skirting canal with five locks on the Virginia side, which opened in 1802. The company failed in 1828, and the Chesapeake and Ohio Canal soon carried the trade along the Maryland bank. Both banks are now National Park Service land, Great Falls Park in Virginia and the C&O Canal National Historical Park in Maryland. A marker at the Virginia overlook shows how high water rose in the great flood of 1936.

• Maryland
  The Old Line State, wrapped around Chesapeake Bay located in
• Virginia
  The Old Dominion, from the Chesapeake to the Blue Ridge located in
• Washington, D.C.
  The federal capital district of the United States near
• Potomac River
  The Nation’s River, flowing past Washington to Chesapeake Bay part of
• The Fall Line
  Where the Piedmont drops to the coastal plain part of