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The Fall Line
Where the Piedmont drops to the coastal plain
The fall line is the natural boundary where the hard, hilly rock of the Piedmont meets the soft, flat sediments of the Atlantic Coastal Plain. Along this line, rivers flowing toward the sea drop in rapids and waterfalls as they leave the harder rock - the "fall" that gives the line its name - and it marks the farthest point upstream that boats could reach from the ocean.
That pairing of waterpower and the head of navigation made the fall line a natural place to build, and a whole string of cities grew up along it: Trenton, Philadelphia, Baltimore, Washington, Richmond, Raleigh, Columbia, Augusta, and Columbus among them. The marker here sits at the falls of the James River in Richmond, Virginia - a classic fall-line city where the rapids running through the heart of downtown still show exactly why the line mattered.