Great Falls is a series of rapids and waterfalls on the

Potomac River The Potomac River () is in the Mid-Atlantic (United States), Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is long,U.S. Geological Survey. National Hydrography D ...

, upstream from

Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

, on the border of

Montgomery County, Maryland Montgomery County is the most populous County (United States), county in the U.S. state of Maryland. As of the 2020 United States census, the county's population was 1,062,061, increasing by 9.3% from 2010. The county seat is Rockville, Maryland ...

and

Fairfax County, Virginia Fairfax County, officially the County of Fairfax, is a County (United States), county in the Commonwealth (U.S. state), Commonwealth of Virginia. With a population of 1,150,309 as of the 2020 United States census, 2020 census, it is the most p ...

. The Potomac and the falls themselves are legally entirely within

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

, since the state's border follows the south bank of the river.

Great Falls Park Great Falls Park is a small National Park Service (NPS) site in Virginia, United States. Situated on along the banks of the Potomac River in northern Fairfax County, the park is a disconnected but integral part of the George Washington Memoria ...

, managed as part of

George Washington Memorial Parkway The George Washington Memorial Parkway, colloquially the G.W. Parkway, is a limited-access road, limited-access parkway that runs along the south bank of the Potomac River from Mount Vernon, Virginia, northwest to McLean, Virginia, and is maint ...

, is on the southern banks in

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

, and

Chesapeake and Ohio Canal National Historical Park The Chesapeake and Ohio Canal National Historical Park is located in the District of Columbia and the state of Maryland. The park was established in 1961 as a National Monument by President Dwight D. Eisenhower to preserve the neglected remains o ...

parkland is along the northern banks of the river in

. Both are operated by the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

. The Great Falls area is popular for outdoor activities such as

kayaking Kayaking is the use of a kayak for moving over water. It is distinguished from canoeing by the sitting position of the paddler and the number of blades on the paddle. A kayak is a low-to-the-water, canoe-like boat in which the paddler sits fac ...

whitewater rafting Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...

rock climbing Rock climbing is a climbing sports discipline that involves ascending climbing routes, routes consisting of natural rock in an outdoor environment, or on artificial resin climbing walls in a mostly indoor environment. Routes are documented in c ...

, and

hiking A hike is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century. Long hikes as part of a religious pilgrimage have existed for a much longer time. "Hi ...

. The Billy Goat Trail on Bear Island, and Olmsted Island, both accessible from Maryland, offer scenic views of the Great Falls. There also are overlook points on the Virginia side. Great Falls and Little Falls (about 5 miles downstream) are named in contradistinction to one another. The river cascades over a series of falls, dropping a total of in elevation over a distance of less than . The Potomac narrows as it passes over the falls and through

Mather Gorge Mather Gorge is a river gorge south and just downriver of Great Falls in the state of Maryland bordering Virginia. The Maryland land side of the gorge is Bear Island, part of the Chesapeake and Ohio Canal National Historical Park, and the Virgin ...

. Heavy rain or snow in the watershed upstream causes white-water floods which entirely submerge the rocks and even threaten the adjacent park visitor center (built on stilts for this reason). A pillar at the Virginia overlook, well above the river, marks the level reached during the 1936 Northeastern United States Floods.

History

The rocks of the falls are about 750 million years old, dating to the late

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

era. The rocks are a resistant metamorphized

schist Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...

, gneisses, metagraywackes, and metaconglomerates. The Falls themselves formed during the Last Glacial Period, about 35,000 years ago, when sea level most recently dropped, causing the Potomac to downcut its valley.

Canals

Multiple canal systems were built around Great Falls. The remains of the Patowmack Canal, built in the 18th century, can be found on the Virginia side. The canal was commissioned by

George Washington George Washington (, 1799) was a Founding Fathers of the United States, Founding Father and the first president of the United States, serving from 1789 to 1797. As commander of the Continental Army, Washington led Patriot (American Revoluti ...

and consisted of a system of five locks to allow barges to avoid the falls. Later on, the

Chesapeake and Ohio Canal The Chesapeake and Ohio Canal, abbreviated as the C&O Canal and occasionally called the Grand Old Ditch, operated from 1831 until 1924 along the Potomac River between Washington, D.C., and Cumberland, Maryland. It replaced the Patowmack Canal ...

was built in the early 19th century on the Maryland side of the falls. It ultimately connected the Potomac tidewater with

Cumberland, Maryland Cumberland is a city in Allegany County, Maryland, United States, and its county seat. At the 2020 United States census, 2020 census, the city had a population of 19,075. Located on the Potomac River, Cumberland is a regional business and comm ...

. The Chesapeake and Ohio Canal also used the Great Falls as a feeder (now abandoned) to supply water for its own use.

Gallery

File:Maryland - Great Falls - NARA - 23941085 (cropped).jpg, Aerial view, 1945 File:Mather Gorge.jpg, Mather Gorge downstream from the falls File:Great Falls Feeder Dam (defunct) at approx 14.12 mi for Chesapeake and Ohio Canal.jpg, Remains of the feeder dam for the

Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Ea ...

and

Ohio Canal The Ohio and Erie Canal was a canal constructed during the 1820s and early 1830s in Ohio. It connected Akron, Ohio, Akron with the Cuyahoga River near its outlet on Lake Erie in Cleveland, Ohio, Cleveland, and a few years later, with the Ohio ...

at Great Falls File:ViewfromOlmstedIslandSouthFootBridge.jpg, Southward view of the

from a

footbridge A footbridge (also a pedestrian bridge, pedestrian overpass, or pedestrian overcrossing) is a bridge designed solely for pedestrians.''Oxford English Dictionary'' While the primary meaning for a bridge is a structure which links "two points at a ...

on Olmsted Island. July 2021. File:Great falls potomac 20200703 083332 VID.webm, View of Great Falls from the Olmsted Island overlook File:Great Falls of the Potomac River January 2014.webm, Great Falls of the Potomac River, between Virginia and Maryland in the United States. January 1, 2014

Panoramas

File:GreatFallsPotomacPanorama.jpg, Great Falls panorama from Virginia File:Potomac Great Falls panorama (from Maryland).jpg, Great Falls panorama from Maryland

References

External links