The Mississippi
The Mississippi is the main river of the United States, flowing south for 6,275 km from northern Minnesota to the Gulf of Mexico. With its main tributary, the Missouri, it forms one of the largest river systems in the world, draining approx. 40% of the land area of the continental United States. The Mississippi is woven through American history, from indigenous trade routes to riverboats to the writing of Mark Twain.
- Length6,275 km(with Missouri tributary)
- CountryUnited StatesPasses through 10 US states
- SourceLake Itasca, MinnesotaA small lake just south of Canada
- MouthGulf of MexicoThrough a huge delta in Louisiana
- Drainage basin3.2 million km²About 40% of the continental USA
- Famous forRiverboats and jazzPlus the city of New Orleans
The Mississippi compared to other great rivers
The Mississippi-Missouri system is the fourth longest river system in the world. Just the Mississippi by itself is 3,766 km long.
What is the Mississippi?
The Mississippi flows from north to south down the centre of the United States. It starts at a small lake in northern Minnesota called Lake Itasca, where you can wade across it. By the time it reaches Louisiana more than 3,700 km later, it is up to 3 km wide and carries an enormous flow of water. The river's name comes from an indigenous Ojibwe word meaning "great river".
The delta and the sediment
The Mississippi carries vast amounts of mud, silt and sand from the centre of America down to the sea. Where it meets the Gulf of Mexico, this sediment piles up into a huge fan-shaped delta. Most of the state of Louisiana is built on Mississippi delta land. The city of New Orleans sits on this delta, much of it below sea level, which makes the city especially vulnerable to floods and hurricanes.
The delta is shrinking. Levees built along the river to control flooding now keep the sediment from reaching the marshes where new land should be forming. As a result, Louisiana loses approx. 80 square km of coastal land every year.
Riverboats and Mark Twain
In the 1800s, the Mississippi was the highway of America. Giant steamboats ferried goods and passengers up and down the river. The American writer Samuel Clemens grew up on the river in Missouri and worked as a steamboat pilot in his twenties. He later took the pen name Mark Twain (a riverboat term meaning "two fathoms deep") and wrote some of the most famous American novels, including The Adventures of Huckleberry Finn, set on the Mississippi.
The river today
The Mississippi is still a vital trade route. Over 500 million tonnes of cargo (grain, coal, oil, chemicals) move along it every year. The river's lower section is fully canalised with locks and dams, allowing large barges to travel from Minneapolis to the Gulf. Major cities along the river include Minneapolis, St Louis, Memphis, Vicksburg, Baton Rouge and New Orleans.
Deeper dive: the Mississippi system, the 1927 flood and the lower river's future
The Mississippi River system is really three rivers joined together: the upper Mississippi (from its source to its confluence with the Missouri near St Louis), the Missouri (which actually carries more water than the upper Mississippi at the junction), and the lower Mississippi (from the Missouri junction to the Gulf). With its tributaries, the Mississippi-Missouri system drains approx. 3.2 million square km of the continental United States, almost 40% of the country's land area. The Ohio River, which joins the Mississippi from the east at Cairo, Illinois, actually carries the most water of all the Mississippi tributaries.
The Great Mississippi Flood of 1927 was one of the worst natural disasters in US history. Heavy rainfall during the winter and spring of 1926-27 caused the river to break through its levees in 145 places, flooding an area of 70,000 square km up to 9 metres deep. Around 200 people were killed directly and roughly 700,000 displaced from their homes. The flood led to the Flood Control Act of 1928 and to a massive federal program of levees, spillways and dams that continues to manage the Mississippi today.
Despite all the engineering, the lower Mississippi is locked in a slow battle with geography. Sediment building up on the current delta has made the river progressively longer and shallower, while a parallel river called the Atchafalaya offers a much shorter route to the Gulf. Left to itself, the Mississippi would already have switched into the Atchafalaya channel, abandoning the current delta and bypassing New Orleans and Baton Rouge entirely. The Old River Control Structure, built in 1963, holds back the river by force, maintaining the current channel against natural pressure. Engineers consider it one of the most critical structures in America. A failure during a major flood could redirect the river permanently within days.
The country is the United States. For the world's biggest river by water volume, see the Amazon.