The longest rivers of the United States include 38 that have
main stem
In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow. ...
s of at least long. The main stem is "the primary downstream segment of a river, as contrasted to its tributaries". The
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
(USGS) defines a main-stem segment by listing coordinates for its two end points, called the ''source'' and the ''mouth''. Some well-known rivers like the
Atchafalaya,
Willamette, and
Susquehanna are not included in this list because their main stems are shorter than 500 miles.
Seven rivers in this list cross or form international boundaries. Two—the
Yukon
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...
and
Columbia
Columbia may refer to:
* Columbia (personification), the historical female national personification of the United States, and a poetic name for America
Places North America Natural features
* Columbia Plateau, a geologic and geographic region i ...
rivers—begin in Canada and flow into the United States. Three—the
Milk
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulat ...
and
Saint Lawrence
Saint Lawrence or Laurence ( la, Laurentius, lit. " laurelled"; 31 December AD 225 – 10 August 258) was one of the seven deacons of the city of Rome under Pope Sixtus II who were martyred in the persecution of the Christians that the Roman ...
rivers and the
Red River of the North
The Red River (french: rivière Rouge or ) is a river in the north-central United States and central Canada. Originating at the confluence of the Bois de Sioux and Otter Tail rivers between the U.S. states of Minnesota and North Dakota, it fl ...
—begin in the United States and flow into Canada. Of these, only the Milk River crosses the international border twice, leaving and then re-entering the United States.
Two rivers, the
Colorado
Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...
and the
Rio Grande
The Rio Grande ( and ), known in Mexico as the Río Bravo del Norte or simply the Río Bravo, is one of the principal rivers (along with the Colorado River) in the southwestern United States and in northern Mexico.
The length of the Rio G ...
, begin in the United States and flow into or form a border with Mexico.
In addition, the
drainage basin
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
s of the
Mississippi
Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...
and
Missouri rivers extend into Canada,
and the basin of the
Gila River
The Gila River (; O'odham ima Keli Akimel or simply Akimel, Quechan: Haa Siʼil, Maricopa language: Xiil) is a tributary of the Colorado River flowing through New Mexico and Arizona in the United States. The river drains an arid watershed of ...
extends into Mexico.
Sources report hydrological quantities with varied precision. Biologist and author
Ruth Patrick
Ruth (or its variants) may refer to:
Places
France
* Château de Ruthie, castle in the commune of Aussurucq in the Pyrénées-Atlantiques département of France
Switzerland
* Ruth, a hamlet in Cologny
United States
* Ruth, Alabama
* Ruth, Ar ...
, describing a table of
high-discharge U.S. rivers, wrote that data on discharge, drainage area, and length varied widely among authors whose works she consulted. "It seems," she said, "that the wisest course is to regard data tables such as the present one as showing the general ranks of rivers, and not to place too much importance on minor (10–20%) differences in figures."
Table
The primary source for watershed and discharge data in the table below is ''Rivers of North America''. Conflicting data from other sources, if the difference is greater than 10 percent, is reported in the notes. Discharge refers to the flow at the mouth. In the "States, provinces, and image" column, the superscripts "s" and "m" indicate "source" and "mouth". Non-U.S. states appear in italics. Except in the "States, provinces, and image" column, abbreviations are as follows: "km" for "kilometer", "mi" for "mile", "s" for "second", "m" for "meter", and "ft" for "foot".
Map
See also
*
List of longest rivers in the United States by state
**
List of longest streams of Idaho
A total of seventy streams that are at least long flow through the U.S. state of Idaho. All of these streams originate in the United States except the Kootenai River (third-longest) and the Moyie River (thirty-first-longest), both of which begi ...
**
List of longest streams of Minnesota
Out of the 6,564 streams that flow through the U.S. State of Minnesota, there are 114 streams that are at least 30 miles long. The second longest river in the United States, the Mississippi River, originates in Minnesota before flowing south t ...
**
List of longest streams of Oregon
Seventy-seven rivers and creeks of at least 50 miles (80 km) in total length are the longest streams of the U.S. state of Oregon. All of these streams originate in the United States except the longest, the Columbia, which begins in the ...
*
List of rivers by length
This is a list of the longest rivers on Earth. It includes river systems over in length.
Definition of length
There are many factors, such as the identification of the source, the identification or the definition of the mouth, and the scale o ...
Notes
References
Works cited
*
*
{{featured list
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 Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
Lists of rivers of the United States
Rivers
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...