A fall line (or fall zone) is the area where an upland region and a

coastal plain A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Co ...

meet and is typically prominent where rivers cross it, with resulting rapids or

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in severa ...

s. The uplands are relatively hard crystalline basement rock, and the

is softer

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

. A fall line often will recede upstream as the river cuts out the uphill dense material, forming "c"-shaped waterfalls and exposing bedrock shoals. Because of these features, riverboats typically cannot travel any farther inland without

portaging Portage or portaging (Canada: ; ) is the practice of carrying water craft or cargo over land, either around an obstacle in a river, or between two bodies of water. A path where items are regularly carried between bodies of water is also called a ...

, unless

locks Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...

are built. The rapid change in elevation of the water and resulting energy release make the fall line a good location for

water mill A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are needed in the production ...

grist mill A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and Wheat middlings, middlings. The term can refer to either the Mill (grinding), grinding mechanism or the building that holds it. Grist i ...

s, and

sawmill A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes (dimensi ...

s. Seeking a head of navigation with a ready supply of water power, people have long made settlements where rivers cross a fall line.

Geography

The slope of fall zones on rivers played a role in settlement patterns. For example, the fall line represents the inland limit of navigation on many rivers. As such, many fall line cities grew around transferring people and goods between land-based and water-based transportation at this point.

Atlantic Seaboard Fall Line

The Atlantic Seaboard Fall Line, or Fall Zone, is a

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''esca ...

where the

Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...

and Atlantic Coastal Plain meet in the eastern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. Much of the Atlantic Seaboard fall line passes through areas where no evidence of

faulting In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

is present. The fall line marks the geologic boundary of hard metamorphosed terrain—the product of the Taconic orogeny—and the sandy, relatively flat outwash plain of the upper continental shelf, formed of unconsolidated

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

and

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

s. Examples of the Fall Zone include the Potomac River's Little Falls and the rapids in Richmond, Virginia, where the James River falls across a series of rapids down to the tidal estuary of the James River.

Columbia, South Carolina Columbia is the List of capitals in the United States, capital of the U.S. state of South Carolina. With a population of 136,632 at the 2020 United States census, 2020 census, it is List of municipalities in South Carolina, the second-largest ...

is similar as well with the Congaree River. Before navigation improvements such as locks, the fall line was often the head of navigation on rivers due to rapids and waterfalls, such as the Little Falls of the

Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augu ...

. Numerous cities were founded at the intersection of rivers and the fall line.

U.S. Route 1 U.S. Route 1 or U.S. Highway 1 (US 1) is a major north–south United States Numbered Highway that serves the East Coast of the United States. It runs from Key West, Florida, north to Fort Kent, Maine, at the Canadian border, making ...

links many of the fall line cities. Mid-Atlantic and Southern U.S. fall line cities include: * Paterson, New Jersey, on the Passaic River *

Trenton, New Jersey Trenton is the capital city of the U.S. state of New Jersey and the county seat of Mercer County. It was the capital of the United States from November 1 to December 24, 1784.Delaware River *

Philadelphia, Pennsylvania Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...

, on the

Schuylkill River The Schuylkill River ( , ) is a river running northwest to southeast in eastern Pennsylvania. The river was improved by navigations into the Schuylkill Canal, and several of its tributaries drain major parts of Pennsylvania's Coal Region. It f ...

Wilmington, Delaware Wilmington (Lenape: ''Paxahakink /'' ''Pakehakink)'' is the largest city in the U.S. state of Delaware. The city was built on the site of Fort Christina, the first Swedish settlement in North America. It lies at the confluence of the Christina ...

, on Brandywine Creek *

Baltimore, Maryland Baltimore ( , locally: or ) is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic (United States), Mid-Atlantic, and List of United States cities by popula ...

, on the

Jones Falls The Jones Falls is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 stream in Maryland. It is impounded to create Lake Roland before running through the city of Baltim ...

, Gunpowder Falls and

Gwynns Falls Gwynns Falls is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011. stream located in Baltimore County and Baltimore City, Maryland. Its headwaters are located in Reisterstow ...

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

, on the

* Fredericksburg, Virginia, on the

Rappahannock River The Rappahannock River is a river in eastern Virginia, in the United States, approximately in length.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011 It traverses the entir ...

* Hanover, Virginia, on the North Anna River * Richmond, Virginia, on the James River *

Petersburg, Virginia Petersburg is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia in the United States. As of the 2020 United States Census, 2020 census, the population was 33,458. The Bureau of Econ ...

, on the Appomattox River *

Weldon, North Carolina Weldon is a town in Halifax County, North Carolina, United States. The population was 1,655 at the 2010 census. It is part of the Roanoke Rapids, North Carolina Micropolitan Statistical Area. History In 1752, Daniel Weldon purchased 1,273 acre ...

, and

Roanoke Rapids, North Carolina Roanoke Rapids () is a city in Halifax County, North Carolina, United States. The population was 15,754 at the 2010 census. It is the principal city of the Roanoke Rapids Micropolitan Statistical Area, and is also an anchor city of the Rocky Mo ...

, on the

Roanoke River The Roanoke River ( ) runs long through southern Virginia and northeastern North Carolina in the United States. A major river of the southeastern United States, it drains a largely rural area of the coastal plain from the eastern edge of the Ap ...

* Rocky Mount, North Carolina, on the Tar River *

Raleigh, North Carolina Raleigh (; ) is the capital city of the state of North Carolina and the seat of Wake County in the United States. It is the second-most populous city in North Carolina, after Charlotte. Raleigh is the tenth-most populous city in the Southe ...

, on the

Neuse River The Neuse River ( , Tuscarora: Neyuherú·kęʔkì·nęʔ) is a river rising in the Piedmont of North Carolina and emptying into Pamlico Sound below New Bern. Its total length is approximately , making it the longest river entirely contained in ...

* Fayetteville, North Carolina, on the

Cape Fear River The Cape Fear River is a long blackwater river in east central North Carolina. It flows into the Atlantic Ocean near Cape Fear, from which it takes its name. The river is formed at the confluence of the Haw River and the Deep River (North Carol ...

Camden, South Carolina Camden is the largest city and county seat of Kershaw County, South Carolina. The population was 7,764 in the 2020 census. It is part of the Columbia, South Carolina, Metropolitan Statistical Area. Camden is the oldest inland city in South C ...

, on the Wateree River *

, on the Congaree River *

Augusta, Georgia Augusta ( ), officially Augusta–Richmond County, is a consolidated city-county on the central eastern border of the U.S. state of Georgia. The city lies across the Savannah River from South Carolina at the head of its navigable portion. Georgi ...

, on the Savannah River * Milledgeville, Georgia, on the

Oconee River The Oconee River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map Accessed April 21, 2011 river in the U.S. state of Georgia. Its origin is in Hall County and it terminates where it joins ...

* Macon, Georgia, on the Ocmulgee River *

Columbus, Georgia Columbus is a consolidated city-county located on the west-central border of the U.S. state of Georgia. Columbus lies on the Chattahoochee River directly across from Phenix City, Alabama. It is the county seat of Muscogee County, with which it ...

, on the Chattahoochee River *

Tallassee, Alabama Tallassee (pronounced ) is a city on the Tallapoosa River, located in both Elmore and Tallapoosa counties in the U.S. state of Alabama. At the 2020 census, the population was 4,763. It is home to a major hydroelectric power plant at Thurlow ...

, on the Tallapoosa River * Wetumpka, Alabama, on the Coosa River *

Tuscaloosa, Alabama Tuscaloosa ( ) is a city in and the seat of Tuscaloosa County in west-central Alabama, United States, on the Black Warrior River where the Gulf Coastal and Piedmont plains meet. Alabama's fifth-largest city, it had an estimated population o ...

, on the

Black Warrior River The Black Warrior River is a waterway in west-central Alabama in the southeastern United States. The river rises in the extreme southern edges of the Appalachian Highlands and flows 178 miles (286 km) to the Tombigbee River, of which the ...

Canada

The

Laurentian Upland The Laurentian Upland (or Laurentian Highlands) is a physiographic region which, when referred to as the "Laurentian Region" or the Grenville geological province, is recognized by Natural Resources Canada as one of five provinces of the larger ...

forms a long scarp line where it meets the Great Lakes–St. Lawrence Lowlands. Along this line numerous rivers have carved falls and canyons (listed East to West): * Saint Anne Falls and Canyon Sainte-Anne ( Sainte-Anne-du-Nord River) *Chaudron à Gaudreault ( Rivière aux Chiens) *Unnamed falls (

Rivière du Sault à la Puce The rivière du Sault à la Puce flows south, on the north shore of the Saint Lawrence river, in the municipality of Château-Richer, in the La Côte-de-Beaupré Regional County Municipality in the administrative region of Capitale-Nationale, in ...

) *Canyon of the Cazeau River * Montmorency Falls ( Montmorency River) * Kabir Kouba Fall ( Saint-Charles River) *Chute Ford ( Sainte-Anne River) *Sainte-Ursule Falls ( Maskinongé River) *Chute à Magnan ( Rivière du Loup) *Chutes Émery and Chute du Moulin Coutu ( Rivière Bayonne) *Les sept chutes ( L'Assomption River) * Dorwin Falls ( Ouareau River) *Wilson Falls ( Rivière du Nord) *Long Sault, now flooded by the

Carillon hydroelectric generating station The Carillon generating station (in French: ''centrale de Carillon'') is a hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electr ...

( Ottawa River) **The

Chaudière Falls , image = Ottawa Chaudiere Falls.jpg , image_size = 300px , caption = Chaudière Falls in June 2006, at summer water levels , map_image = , map_size = , coordinates = , coords_ref = , location ...

run over the unrelated Eardley Escarpment of the Ottawa-Bonnechere Graben The

Jacques-Cartier River The Jacques-Cartier River is a river in the province of Quebec, Canada. It is 161 km long and its source is Jacques-Cartier Lake in Laurentides Wildlife Reserve, and flows in a predominantly southern direction before ending in the Saint Lawr ...

and Saint-Maurice River lack such noticeable feature because they cross the scarp through

U-shaped valley U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight s ...

s. The falls of the lower Saint-Maurice (as well as those of the Beauport River, in

Quebec City Quebec City ( or ; french: Ville de Québec), officially Québec (), is the capital city of the Canadian province of Quebec. As of July 2021, the city had a population of 549,459, and the metropolitan area had a population of 839,311. It is t ...

) are due to the

fluvial terrace Fluvial terraces are elongated terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial t ...

s of the

Saint Lawrence river The St. Lawrence River (french: Fleuve Saint-Laurent, ) is a large river in the middle latitudes of North America. Its headwaters begin flowing from Lake Ontario in a (roughly) northeasterly direction, into the Gulf of St. Lawrence, connectin ...

rather than the Laurentian Scarp.

References

External links

* {{DEFAULTSORT:Fall Line Geographic coordinate lists Geomorphology

Geography

Atlantic Seaboard Fall Line

Canada

See also

References

External links