Missouri River

Missouri River
Pekitanoui,[1] Big Muddy,[2] Mighty Mo, Wide Missouri, Kícpaarukstiʾ,[3] Lakota: Mnišoše[4][5]
Lower Missouri River.jpg
A relatively undeveloped reach of the river near Rocheport, Missouri
Missouri River basin map.png
Map of the Missouri River and its tributaries in
North America
EtymologyThe Missouri tribe, whose name in turn meant "people with wooden canoes"[1]
CountryUnited States
StateMontana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, Missouri
CitiesGreat Falls, MT, Bismarck, ND, Pierre, SD, Sioux City, IA, Omaha, NE, Saint Joseph, MO, Kansas City, KS, Kansas City, MO, St. Louis, MO
Physical characteristics
SourceHell Roaring Creek–Red Rock RiverBeaverhead RiverJefferson River
 ⁃ locationnear Brower's Spring, Montana
 ⁃ coordinates44°33′02″N 111°28′21″W / 44°33′02″N 111°28′21″W / 44.55056; -111.47250[6][7]
 ⁃ length295 mi (475 km)
 ⁃ elevation9,100 ft (2,800 m)
2nd sourceFirehole RiverMadison River
 ⁃ locationMadison Lake, Yellowstone National Park, Wyoming
 ⁃ coordinates44°20′55″N 110°51′53″W / 44°20′55″N 110°51′53″W / 44.34861; -110.86472[8]
 ⁃ length183 mi (295 km)
 ⁃ elevation8,215 ft (2,504 m)
Source confluenceMissouri Headwaters State Park
 ⁃ locationThree Forks, Montana
 ⁃ coordinates45°55′39″N 111°20′39″W / 45°55′39″N 111°20′39″W / 45.92750; -111.34417[1]
 ⁃ elevation4,042 ft (1,232 m)
MouthMississippi River
 ⁃ location
Spanish Lake, near St. Louis, Missouri
 ⁃ coordinates
38°48′49″N 90°07′11″W / 38°48′49″N 90°07′11″W / 38.81361; -90.11972750,000 cu ft/s (21,000 m3/s)[11]
Basin features
 ⁃ leftJefferson, Dearborn, Sun, Marias, Milk, James, Big Sioux, Grand, Chariton
 ⁃ rightMadison, Gallatin, Yellowstone, Little Missouri, Cheyenne, White, Niobrara, Platte, Kansas, Osage, Gasconade
TypeWild, Scenic, Recreational

The Missouri River is the longest river in North America.[13] Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2,341 miles (3,767 km)[9] 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[14] and carries a comparable volume of water.[10][15] When combined with the lower Mississippi River, it forms the world's fourth longest river system.[13]

For over 12,000 years, people have depended on the Missouri River and its tributaries as a source of sustenance and transportation. More than ten major groups of Native Americans populated the watershed, most leading a nomadic lifestyle and dependent on enormous bison herds that roamed through the Great Plains. The first Europeans encountered the river in the late seventeenth century, and the region passed through Spanish and French hands before becoming part of the United States through the Louisiana Purchase.

The Missouri River was one of the main routes for the westward expansion of the United States during the 19th century. The growth of the fur trade in the early 19th century laid much of the groundwork as trappers explored the region and blazed trails. Pioneers headed west en masse beginning in the 1830s, first by covered wagon, then by the growing numbers of steamboats that entered service on the river. Settlers took over former Native American lands in the watershed, leading to some of the most longstanding and violent wars against indigenous peoples in American history.

During the 20th century, the Missouri River basin was extensively developed for irrigation, flood control and the generation of hydroelectric power. Fifteen dams impound the main stem of the river, with hundreds more on tributaries. Meanders have been cut and the river channelized to improve navigation, reducing its length by almost 200 miles (320 km) from pre-development times. Although the lower Missouri valley is now a populous and highly productive agricultural and industrial region, heavy development has taken its toll on wildlife and fish populations as well as water quality.

The flooding along the Missouri which began during the spring 2019 Midwestern U.S. floods is expected to persist through the winter.[16]


From the Rocky Mountains, three streams rise to form the headwaters of the Missouri River:

View of a deep blue lake surrounded by low mountains
Holter Lake, a reservoir on the upper Missouri River

The Missouri River officially starts at the confluence of the Jefferson and Madison in Missouri Headwaters State Park near Three Forks, Montana, and is joined by the Gallatin a mile (1.6 km) downstream. It then passes through Canyon Ferry Lake, a reservoir west of the Big Belt Mountains. Issuing from the mountains near Cascade, the river flows northeast to the city of Great Falls, where it drops over the Great Falls of the Missouri, a series of five substantial waterfalls. It then winds east through a scenic region of canyons and badlands known as the Missouri Breaks, receiving the Marias River from the west then widening into the Fort Peck Lake reservoir a few miles above the confluence with the Musselshell River. Farther on, the river passes through the Fort Peck Dam, and immediately downstream, the Milk River joins from the north.[17][18]

Flowing eastward through the plains of eastern Montana, the Missouri receives the Poplar River from the north before crossing into North Dakota where the Yellowstone River, its greatest tributary by volume, joins from the southwest. At the confluence, the Yellowstone is actually the larger river.[n 1] The Missouri then meanders east past Williston and into Lake Sakakawea, the reservoir formed by Garrison Dam. Below the dam the Missouri receives the Knife River from the west and flows south to Bismarck, the capital of North Dakota, where the Heart River joins from the west. It slows into the Lake Oahe reservoir just before the Cannonball River confluence. While it continues south, eventually reaching Oahe Dam in South Dakota, the Grand, Moreau and Cheyenne Rivers all join the Missouri from the west.[17][18]

The Missouri makes a bend to the southeast as it winds through the Great Plains, receiving the Niobrara River and many smaller tributaries from the southwest. It then proceeds to form the boundary of South Dakota and Nebraska, then after being joined by the James River from the north, forms the Iowa–Nebraska boundary. At Sioux City the Big Sioux River comes in from the north. The Missouri flows south to the city of Omaha where it receives its longest tributary, the Platte River, from the west.[21] Downstream, it begins to define the Nebraska–Missouri border, then flows between Missouri and Kansas. The Missouri swings east at Kansas City, where the Kansas River enters from the west, and so on into north-central Missouri. To the east of Kansas City, the Missouri receives, on the left side, the Grand River. It passes south of Columbia and receives the Osage and Gasconade Rivers from the south downstream of Jefferson City. The river then rounds the northern side of St. Louis to join the Mississippi River on the border between Missouri and Illinois.[17][18]

Other Languages
Afrikaans: Missouririvier
العربية: نهر ميزوري
asturianu: Ríu Misuri
Avañe'ẽ: Ysyry Misuri
azərbaycanca: Missuri çayı
تۆرکجه: میزوری چایی
Bân-lâm-gú: Missouri Hô
башҡортса: Миссури (йылға)
беларуская: Місуры (рака)
भोजपुरी: मिसौरी नदी
български: Мисури
brezhoneg: Missouri (stêr)
català: Riu Missouri
čeština: Missouri (řeka)
Cymraeg: Afon Missouri
eesti: Missouri
español: Río Misuri
Esperanto: Misuro (rivero)
한국어: 미주리강
हिन्दी: मिसोरी नदी
hornjoserbsce: Missouri River
Bahasa Indonesia: Sungai Missouri
íslenska: Missouri-fljót
Kiswahili: Missouri (mto)
Kreyòl ayisyen: Misouri (rivyè)
Кыргызча: Миссури
Latina: Missurius
latviešu: Misūri (upe)
lietuvių: Misūris (upė)
македонски: Мисури (река)
മലയാളം: മിസോറി നദി
Mirandés: Riu Missouri
Nederlands: Missouri (rivier)
नेपाल भाषा: मिजौरी खुसि
日本語: ミズーリ川
norsk nynorsk: Missourielva
oʻzbekcha/ўзбекча: Missuri (daryo)
Piemontèis: Missouri (fium)
português: Rio Missouri
Runa Simi: Missouri mayu
Simple English: Missouri River
slovenčina: Missouri (rieka)
slovenščina: Misuri (reka)
српски / srpski: Мисури (река)
srpskohrvatski / српскохрватски: Missouri (rijeka)
Türkçe: Missouri Nehri
українська: Міссурі (річка)
Tiếng Việt: Sông Missouri
吴语: 密苏里河
ייִדיש: מיזורי טייך
粵語: 密蘇里河
中文: 密苏里河