River source

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River Wey near its source at Farringdon Wey source farringdon.jpg
River Wey near its source at Farringdon

The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source.



A stone near Crissolo, Italy, inscribed: Here is born the Po SorgentePo.jpg
A stone near Crissolo, Italy, inscribed: Here is born the Po

The United States Geological Survey (USGS) states that a river's "length may be considered to be the distance from the mouth to the most distant headwater source (irrespective of stream name), or from the mouth to the headwaters of the stream commonly known as the source stream". As an example of the second definition above, the USGS at times considers the Missouri River as a tributary of the Mississippi River. But it also follows the first definition above (along with virtually all other geographic authorities and publications) in using the combined Missouri - lower Mississippi length figure in lists of lengths of rivers around the world. [1] Most rivers have numerous tributaries and change names often; it is customary to regard the longest tributary or stem as the source, regardless of what name that watercourse may carry on local maps and in local usage.[ citation needed ]

This most commonly identified definition of a river source specifically uses the most distant point (along watercourses from the river mouth) in the drainage basin from which water runs year-around (perennially), or, alternatively, as the furthest point from which water could possibly flow ephemerally. [2] The latter definition includes sometimes-dry channels and removes any possible definitions that would have the river source "move around" from month to month depending on precipitation or ground water levels. This definition, from geographer Andrew Johnston of the Smithsonian Institution, is also used by the National Geographic Society when pinpointing the source of rivers such as the Amazon or Nile. A definition given by the state of Montana agrees, stating that a river source is never a confluence but is "in a location that is the farthest, along water miles, from where that river ends." [3]

Under this definition neither a lake (excepting lakes with no inflows) nor a confluence of tributaries can be a true river source, though both often provide the starting point for the portion of a river carrying a single name. For example, National Geographic and virtually every other geographic authority and atlas define the source of the Nile River not as Lake Victoria's outlet where the name "Nile" first appears, which would reduce the Nile's length by over 900 km (560 mi) (dropping it to fourth or fifth on the list of world's rivers), but instead use the source of the largest river flowing into the lake, the Kagera River. Likewise, the source of the Amazon River has been determined this way, even though the river changes names numerous times along its course. [4] However, the source of the Thames in England is traditionally reckoned according to the named river Thames rather than its longer tributary, the Churn although not without contention. [5]

When not listing river lengths, however, alternative definitions may be used. The Missouri River's source is named by some USGS and other federal and state agency sources, following Lewis and Clark's naming convention, as the confluence of the Madison and Jefferson Rivers, rather than the source of its longest tributary (the Jefferson). [3] This contradicts the most common definition, [6] which is, according to a US Army Corps of Engineers official on a USGS site, that "[geographers] generally follow the longest tributary to identify the source of rivers and streams." In the case of the Missouri River, this would have the source be well upstream from Lewis and Clark's confluence, "following the Jefferson River to the Beaverhead River to Red Rock River, then Red Rock Creek to Hell Roaring Creek."[ citation needed ]

Characteristics of sources

Rhume Spring, source of the Rhume river Rhumequelle Rhumspringe.jpg
Rhume Spring, source of the Rhume river

Sometimes the source of the most remote tributary may be in an area that is more marsh-like, in which the "uppermost" or most remote section of the marsh would be the true source. For example, the source of the River Tees is marshland.

The furthest stream is also often called the head stream. Headwaters are often small streams with cool waters because of shade and recently melted ice or snow. They may also be glacial headwaters, waters formed by the melting of glacial ice.

Headwater areas are the upstream areas of a watershed, as opposed to the outflow or discharge of a watershed. The river source is often but not always on or quite near the edge of the watershed, or watershed divide. For example, the source of the Colorado River is at the Continental Divide separating the Atlantic Ocean and Pacific Ocean watersheds of North America.


A river is considered a linear geographic feature, with only one mouth and one source. For an example, note how the Mississippi River and Missouri River sources are officially defined:

The verb "rise" can be used to express the general region of a river's source, and is often qualified with an adverbial expression of place. For example:

The word "source", when applied to lakes rather than rivers or streams, refers to the lake's inflow. [7] [8]

See also

Related Research Articles

Missouri River Major river in the central United States

The Missouri River is the longest river in North America. Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri. The river drains a sparsely populated, semi-arid watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces. Although nominally considered a tributary of the Mississippi, the Missouri River above the confluence is much longer and carries a comparable volume of water. When combined with the lower Mississippi River, it forms the world's fourth longest river system.

Lake Itasca lake in Clearwater County, northern Minnesota, United States

Lake Itasca is a small glacial lake approximately 1.8 square miles in area. It is notable for being the headwaters of the Mississippi River, and is located in southeastern Clearwater County, in the Headwaters area of north central Minnesota. The lake is within Itasca State Park and has an average depth of 20 to 35 feet (6–11 m), and is 1,475 ft (450 m) above sea level.

Jefferson River river in the United States of America

The Jefferson River is a tributary of the Missouri River, approximately 83 miles (134 km) long, in the U.S. state of Montana. The Jefferson River and the Madison River form the official beginning of the Missouri at Missouri Headwaters State Park near Three Forks. It is joined 0.6 miles (1.0 km) downstream (northeast) by the Gallatin.

Current River (Ozarks) river in Missouri, United States

The Current River forms in the southeastern portion of the Ozarks of Missouri and becomes a 7th order stream as it flows southeasterly out of the Ozarks into northeastern Arkansas where it becomes a tributary of the Black River, which is a tributary of the White River, a tributary of the Mississippi River. The Current River is approximately 184 miles (296 km) long and drains about 2,641 square miles (6,840 km2) of land mostly in Missouri and a small portion of land in northeastern Arkansas. The headwaters of the Current River are nearly 900 feet (270 m) above sea level, while the mouth of the river lies around 280 feet (85 m) above sea level. The basin drains a rural area that is dominated by karst topography, underlain by dolomite and sandstone bedrock with a small area of igneous rock southeast of Eminence, Missouri. The annual daily mean discharge of the river near Doniphan, Missouri is 2,815 cubic feet (79.7 m3) per second. In 1964, over 134 mi (160 km) of the upper course of the river and its tributaries were federally protected as the Ozark National Scenic Riverways, the first national park in America to protect a river system.

Feather River river in the United States of America

The Feather River is the principal tributary of the Sacramento River, in the Sacramento Valley of Northern California. The river's main stem is about 73 miles (117 km) long. Its length to its most distant headwater tributary is just over 210 miles (340 km). The main stem Feather River begins in Lake Oroville, where its four long tributary forks join together—the South Fork, Middle Fork, North Fork, and West Branch Feather Rivers. These and other tributaries drain part of the northern Sierra Nevada, and the extreme southern Cascades, as well as a small portion of the Sacramento Valley. The total drainage basin is about 6,200 square miles (16,000 km2), with approximately 3,604 square miles (9,330 km2) above Lake Oroville.

Drainage divide Elevated terrain that separates neighbouring drainage basins

In topography, a drainage divide, water divide, divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be harder to discern.

Black River (Arkansas–Missouri) river in Missouri and Arkansas

The Black River is a tributary of the White River, about 300 miles (480 km) long, in southeastern Missouri and northeastern Arkansas in the United States. Via the White River, it is part of the Mississippi River watershed. Black River Technical College is named for the river.

Big Muddy River river in the United States of America

The Big Muddy River is a 156-mile-long (251 km) river in southern Illinois. It joins the Mississippi River just south of Grand Tower. The Big Muddy has been dammed near Benton, forming Rend Lake.

Confluence Meeting of two or more bodies of flowing water

In geography, a confluence occurs where two or more flowing bodies of water join together to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river ; or where two streams meet to become the source of a river of a new name ; or where two separated channels of a river rejoin at the downstream end.

Little River (St. Francis River tributary) tributary of the St. Francis River, Missouri and Arkansas, United States of America

The Little River is a tributary of the St. Francis River, about 148 miles (238 km) long, in southeastern Missouri and northeastern Arkansas in the United States. Via the St. Francis, it is part of the watershed of the Mississippi River.

Dowagiac River river in the United States of America

The Dowagiac River is a southwesterly flowing 30.9-mile-long (49.7 km) stream in the Lower Peninsula of the U.S. state of Michigan. It is tributary to the St. Joseph River which flows, in turn, into eastern Lake Michigan.

North Fork Feather River river in the United States of America

The North Fork Feather River is a watercourse of the northern Sierra Nevada in the U.S. state of California. It flows generally southwards from its headwaters near Lassen Peak to Lake Oroville, a reservoir formed by Oroville Dam in the foothills of the Sierra, where it runs into the Feather River. The river drains about 2,100 square miles (5,400 km2) of the western slope of the Sierras. By discharge, it is the largest tributary of the Feather.

The stream order or waterbody order is a positive whole number used in geomorphology and hydrology to indicate the level of branching in a river system.

Fall Creek is a small creek with headwaters in Stone County just south of Missouri Route 76 and northeast of Silver Dollar City. The stream enters Taney County and flows southeast between Route 76 and Missouri Route 265 through west Branson and joins the White River downstream of the Table Rock Lake dam in south Branson. It flows parallel to and then under Missouri Route 165. The White River enters Lake Taneycomo downstream.

Neepaulakating Creek stream in Sussex County, New Jersey

Neepaulakating Creek is a 2.4-mile long (3.8 km) tributary of Papakating Creek in Wantage Township in Sussex County, New Jersey in the United States. It is one of three streams feeding the Papakating Creek, a major contributor to the Wallkill River. Although the stream was dammed in the 1950s to create Lake Neepaulin as the focal point of a private residential development, the stream did not receive a name until 2002. Residents chose a name that combined elements of the names "Neepaulin" and "Papakating", and submitted a proposal to the United States Board of Geographic Names. The name was approved in 2004.

Brush Creek is a stream in Crawford and Gasconade counties in the U.S. state of Missouri. It is tributary to the Bourbeuse River.

Maupin Creek is a stream in Franklin and Jefferson Counties in the U.S. state of Missouri. It is a tributary of Big River.

Silver Creek is a stream in southwestern Randolph County and the southeast corner of Chariton County in north central Missouri. It is a tributary of the East Fork Little Chariton River with the confluence in Chariton County. The headwaters of Silver Creek are just northwest of Higbee.

Kitten Creek is a stream in St. Clair and Vernon County in the U.S. state of Missouri. It is a tributary of Clear Creek.


  1. "Largest Rivers in the United States" (PDF). United States Geological Survey . Retrieved 24 October 2009.
  2. "National Geographic News @ nationalgeographic.com". news.nationalgeographic.com.
  3. 1 2 "The True Utmost Reaches of the Missouri".
  4. "IBGE - Instituto Brasileiro de Geografia e Estatística". Archived from the original on 2011-06-15.
  5. Bailey, David (15 May 2012). "Could the River Thames be longer than the River Severn?" via www.bbc.co.uk.
  6. "CERC Science Topic: Missouri River" (PDF). infolink.cr.usgs.gov.
  7. "Owens Valley Particulate Matter Plan: Q & A". Environmental Protection Agency . Retrieved 2008-05-30. ...the Owens River, the source of the lake...
  8. Jorge Enrique Casallas Guzmán (2004-02-11). "Limnological investigations in Lake San Pablo" (PDF). Archived from the original (PDF) on 2008-06-25. Retrieved 2008-05-30. ...source of the lake is the River Itambi...