The One Minute Geographer: The Great American Fall Line

Rapids at the Fall Line on the James River at Richmond, VA. Photo from americanrivers.org

The One Minute Geographer started a series, now and then, about important LINES in American geography. Followers will recall the Magical Meridian about the 100-degree longitude line and the 20-inch rainfall line associated with it. There are a lot more lines! We’re also asking ‘Why are cities located where they are?’

Today, lets look at the Fall Line that runs through many of the Atlantic Coast states, technically, in a geological sense, from New Jersey to the Georgia-Alabama border.

Some Fall Line cities. (Note that New York is shown for locational purposes; it is not a Fall Line city.) Map from gotbooks.miracosta.edu/geology

The Fall Line is the meeting place of the Piedmont region and the Coastal Plain. Very generally, the Piedmont (French for ‘foot of the mountains’) is the bedrock underlying the Appalachians mountains to the west. The Coastal Plain is the flatter sandy soil to the east, much of it the debris from the eroded Appalachian Mountain chain that used to be as tall as the Rockies or the Alps.

The Fall Line, really a zone that is often less than a mile wide, is series of falls and rapids exposed where the rivers running from the Appalachians to the ocean have cut down to the underlying bedrock. An ocean-going ship traveling inland and up-river from the coast…