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{{Short description|Escarpment in the Eastern United States}}
{{Cleanup reorganize|date=August 2025}}
{{Infobox landform
| water =
| name = Atlantic Seaboard fall line
| other_name =
| type = [[Escarpment]]
| photo =
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<!-- map -->
| map =
| relief =
| map_image = United States Fall Line.jpg
| map_caption = Map showing part of the Eastern Seaboard Fall Line where the pale-colored coastal plain meets the brightly colored Piedmont.
<!-- ___location -->
| ___location = United States
| coordinates =
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| elevation_ft = <!-- or |elevation_m = -->
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| surface_elevation_ft = <!-- or |surface_elevation_m = -->
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| highest_point =
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| length = {{convert|900|mi|km|abbr=on}}<ref name=freitag/>
| width =
| area =
| depth =
| drop =
| formed_by = [[New Jersey]], [[Virginia]], the [[Carolinas]], [[Georgia (U.S. state)|Georgia]], [[Alabama]], U.S.<ref name=USGS>{{Cite web|title=The Fall Line |url=http://tapestry.usgs.gov/features/14fallline.html |work=A Tapestry of Time and Terrain: The Union of Two Maps - Geology and Topography |publisher=USGS.gov |access-date=2010-08-12 |url-status=dead }}{{dead link|date=August 2025}}</ref><ref name="georgia">{{Cite web|title=Georgia Geology |url=http://www.gly.uga.edu/default.php?PK=0&iPage=5#FallLine |access-date=2010-08-13 |archive-url=https://web.archive.org/web/20100904194712/http://www.gly.uga.edu/default.php?PK=0&iPage=5 |archive-date=4 September 2010 <!--DASHBot--> |url-status=live }}</ref><ref name=freitag/>
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}}
{{GeoGroupTemplate|align=left}}
The '''Atlantic Seaboard Fall Line''', or '''Fall Zone''', is a {{convert|900|mi|km|adj=on}} [[escarpment]] where the [[Piedmont (United States)|Piedmont]] and [[Atlantic coastal plain]] meet in the [[eastern United States]].<ref name=freitag>{{cite book |last= Freitag |first= Bob |author2=Susan Bolton |author3=Frank Westerlund |author4=Julie Clark |title= Floodplain Management: A New Approach for a New Era |year= 2009 |publisher= Island Press |isbn= 978-1-59726-635-2 |page= 77 |url= https://books.google.com/books?id=e1lr3gQiO8gC&pg=PA77 |access-date= 17 November 2010}}</ref> Much of the Atlantic Seaboard fall line passes through areas where no evidence of [[faulting]] is present.
The [[fall line]] marks the geologic boundary of hard metamorphosed terrain—the product of the [[Taconic orogeny]]—and the sandy, relatively flat [[alluvial plain]] of the upper continental shelf, formed of unconsolidated [[Cretaceous]] and [[Cenozoic]] [[sediment]]s. Examples of Fall Zone features include the [[Little Falls (Potomac River)|Potomac River's Little Falls]] and the rapids in [[Richmond, Virginia]], where the [[James River]] falls across a series of rapids down to its own tidal estuary.
Before navigation improvements, such as locks, the fall line was generally the [[wikt:head of navigation|head of navigation]] on rivers due to their rapids or waterfalls, and the necessary [[portage]] around them. Numerous cities initially formed along the fall line because of the easy river transportation to seaports, as well as the availability of water power to operate mills and factories, thus bringing together river traffic and industrial labor. [[U.S. Route 1]] and [[Interstate 95|I-95]] link many of the fall-line cities.
In 1808, [[United States Secretary of the Treasury|Treasury Secretary]] [[Albert Gallatin]] noted the significance of the fall line as an obstacle to improved national communication and commerce between the Atlantic seaboard and the western river systems:<ref>[Report on] Roads and Canals, Communicated to the Senate April 4, 1808, [http://memory.loc.gov/cgi-bin/ampage?collId=llsp&fileName=037/llsp037.db&recNum=736 p.729]</ref>
{{Quote|The most prominent, though not perhaps the most insuperable obstacle in the navigation of the Atlantic rivers, consists in their lower falls, which are ascribed to a presumed continuous granite ridge, rising about one hundred and thirty feet above tide water. That ridge from New York to James River inclusively arrests the ascent of the tide; the falls of every river within that space being precisely at the head of the tide; pursuing thence southwardly a direction nearly parallel to the mountains, it recedes from the sea, leaving in each southern river an extent of good navigation between the tide and the falls. Other falls of less magnitude are found at the gaps of the [[Blue Ridge Mountains|Blue Ridge]], through which the rivers have forced their passage...}}
Gallatin's observation was sound, though simplified and limited by the knowledge of his time. The limits of the Fall Line are subject to some dispute. In the north, the fall line is usually understood to have its northern limit at New Brunswick, a geologic continuation in fact crosses the [[Hackensack River|Hackensack]] and [[Passaic River|Passaic]] Rivers at the cities of those names, to which navigation was possible. In the south, some such as Gallatin above, and the USGS source in the infobox, imply its end to be in the Carolinas or Georgia, and to include only rivers running to the Atlantic; but it is more accurate, as the Georgia source in the infobox does, to trace it farther west through Georgia and Alabama, as that is the geologic continuation.<ref>[https://www.loc.gov/ghe/cascade/index.html?appid=8caec0ea0f45442396e539c227ee192c], especially the first section and maps.</ref>
== Cities and towns ==
Only the principal city of an area is listed below. However, two cities may belong on one river, if the one downstream is at the effective head of navigation and the one upstream at the site of useful water power.
Some cities that lie along the Piedmont–Coastal Plain fall line include the following (from north to south):
* [[New Brunswick, New Jersey]] on the [[Raritan River]].
* [[Trenton, New Jersey]], on the [[Delaware River]].<ref name=freitag/>
* [[Philadelphia|Philadelphia, Pennsylvania]], on the [[Schuylkill River]].<ref name=shamsi>{{cite book |last= Shamsi |first= Nayyar |title= Encyclopaedia of Political Geography |year= 2006 |publisher= Anmol Publications |isbn= 978-81-261-2406-0 |pages= 92–93 |url= https://books.google.com/books?id=4Z2Kh7ELI0oC&pg=PA92 |access-date= 17 November 2010}}</ref>
* [[Wilmington, Delaware]], on the [[Brandywine Creek (Christina River tributary)|Brandywine River]].
* [[Havre de Grace, Maryland]], on the [[Susquehanna River]]/head of [[Chesapeake Bay]].
* [[Baltimore|Baltimore, Maryland]], on [[Herring Run]], [[Jones Falls]], and [[Gwynns Falls]].<ref>{{cite web |url= http://www.mgs.md.gov/geology/ |title= Maryland Geology |publisher= Maryland Geological Society |access-date= 25 January 2017}}</ref>
* [[Washington, D.C.]], on the [[Potomac River]].<ref name=deane>{{cite book |last= Deane |first= Winegar |title= Highroad Guide to Chesapeake Bay |year= 2002 |publisher= John F. Blair |isbn= 978-0-89587-279-1 |page= 5 |url= https://books.google.com/books?id=bMejFkODGIcC&pg=PA5 |access-date= 17 November 2010}}</ref>
* [[Fredericksburg, Virginia]] on the [[Rappahannock River]].<ref name=deane/>
* [[Richmond, Virginia]], on the [[James River]].<ref name=roberts>{{cite book |last= Roberts |first= David C. |author2=W. Grant Hodsdon |editor= Roger Tory Peterson |title= A Field Guide to Geology: Eastern North America |year= 2001 |publisher= Houghton Mifflin Harcourt |isbn= 978-0-618-16438-7 |page= 242 |url= https://books.google.com/books?id=zNJO2VBVRPIC&pg=PA242 |access-date= 17 November 2010}}</ref>
* [[Goldsboro, North Carolina]] and [[Smithfield, North Carolina]], on the [[Neuse River]].<ref name=ncpedia>{{cite web |url= http://www.ncpedia.org/fall-line |title= Fall Line |publisher= NCpedia |access-date= 25 January 2017}}</ref>
* [[Fayetteville, North Carolina]], on the [[Cape Fear River]].{{citation needed|date=August 2025}}
* [[Columbia, South Carolina]], on the [[Congaree River]].<ref name=georgia/><ref name=roberts/>
* [[Augusta, Georgia]], on the [[Savannah River]].<ref name=georgia/>
* [[Macon, Georgia]], on the [[Ocmulgee River]].<ref name=georgia/>
* [[Columbus, Georgia]], on the [[Chattahoochee River]].<ref name=georgia/>
* [[Tuscaloosa, Alabama]], on the [[Black Warrior River]].<ref name=georgia/>
==Geographic coordinates==
{{Expand list|date=June 2010}}
{|class="wikitable"
|+valign=top style="background:silver" |Atlantic Seaboard fall line, north-to-south
! | <small>State</small>
! | <small>Point (crossing)</small>
! | <small>Elevation & coordinates</small>
! | <small>Fall zone:<br/>drop/width (slope)</small>
! | <small>Geomorphology<br/>Piedmont—Coastal plain</small>
|-
|rowspan=2 |[[New Jersey]]
| [[New Brunswick, New Jersey|New Brunswick]] ([[Raritan River]])
| {{convert|460|ft|m|abbr=on}} <small>{{Coord|40|29|18|N|74|26|52|W|region:US-NJ_type:city}}</small>
|
|-
| [[Trenton, New Jersey|Trenton]] ([[Delaware River]])
| align=right |<small>{{Coord|40|13|18|N|74|45|22|W|region:US-NJ_type:city}}</small>
| 8 ft
|
|-
|rowspan=1 |[[Pennsylvania]]
|[[Philadelphia]] ([[Schuylkill River]] by [[Interstate 76 (east)|I-76]])
| align=right |<small>{{Coord|39|57|13|N|75|10|17|W|region:US-PA_type:city}}</small>
|
|
|-
|rowspan=1 |[[Delaware]]
|[[Wilmington, Delaware|Wilmington]] ([[Brandywine Creek (Christina River)|Brandywine Creek]])
| align=right |<small>{{Coord|39|44|42|N|75|32|54|W|region:US-DE_type:city}}</small>
|
|
|-
|rowspan=1 |[[Delaware]]
|[[Newark, Delaware|Newark]] ([[White Clay Creek (Christina River)|White Clay Creek]])
| align=right |<small>{{Coord|39|40|39|N|75|45|26|W|region:US-DE_type:city}}</small>
|
|
|-
|rowspan=3 | [[Maryland]]
| [[Conowingo Dam]] ([[Susquehanna River|Susquehanna]])
|
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|-
| [[Ellicott City, Maryland|Ellicott City]]<ref>{{Cite web|title=History/Culture |url=http://www.patapscoheritagegreenway.org/history/HistPersp.html |publisher=PatapscoHeritageGreenway.org |access-date=2010-09-07 |quote=George Ellicott House: A block away is the 1789 George Ellicott House at 24 Frederick Road., which has been saved, moved out of the flood plain, and restored. The Ellicott family settled here along the fall line of the Patapsco River in 1772 and built an innovative, water-powered flour mill |url-status=dead |archive-url=https://web.archive.org/web/20100310084026/http://www.patapscoheritagegreenway.org/history/HistPersp.html |archive-date=2010-03-10 }}</ref> ([[Patapsco River|Patapsco]])
| align=right |<small>{{Coord|39|16.044|N|76|47.573|W|region:US-MD_type:city}}[http://www.hmdb.org/Marker.asp?Marker=193]</small>
|
| Crystalline rock—unconsolidate marine sediments<ref>{{cite web |url=http://www.mde.maryland.gov/assets/document/Patapsco%20LNB%20Stressor%20ID%20Report_04-20-09.pdf |archive-url=https://web.archive.org/web/20090621075548/http://www.mde.maryland.gov/assets/document/Patapsco%20LNB%20Stressor%20ID%20Report_04-20-09.pdf |archive-date=2009-06-21 |title=Watershed Report for Biological Impairment of the Patapsco Lower North Branch Watershed in Anne Arundel, Baltimore, Carroll, and Howard Counties and Baltimore City, Maryland. Biological Stressor Identification Analysis. Results and Interpretation |work=Maryland Department of the Environment |date=April 2009 }}</ref>
|-
| [[Little Falls (Potomac River)]]
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|-
|rowspan=1 | [[Washington, DC]]
|[[Theodore Roosevelt Island]] ([[Potomac River]])
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|-
| rowspan="3" | [[Virginia]]
| [[Fredericksburg, Virginia|Fredericksburg]] ([[Rappahannock River|Rappahannock]])
| align=right |<small>{{Coord|38|18.11|N|77|28.25|W|region:US-VA_type:city}}[http://www.hmdb.org/Marker.asp?Marker=193]</small>
|
| [west of [[Interstate 95]] bridge]<ref>{{Cite web |title=Fall Line |url=http://www.virginiaplaces.org/regions/fallshape.html |publisher=VirginiaPlaces.org |access-date=2010-08-13}}</ref>
|-
|[[Richmond, Virginia|Richmond]] ([[James River]])
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|-
| [[Emporia, Virginia|Emporia]] ([[Meherrin River]])<ref>{{Cite web |title=River and "Fall Line" Cities |url=http://www.virginiaplaces.org/vacities/24river.html |publisher=VirginiaPlaces.org |access-date=2010-08-13}}</ref>
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==References==
{{Reflist}}
[[Category:East Coast of the United States]]
[[Category:Escarpments of the United States]]
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