The Mississippi River is 2,300 miles (3,700 km) long. This, the largest river system in North America, is an aulacogen of the Mid-Atlantic Ridge. If measured from the head of the Missouri River, the length of the Missouri/Mississippi combination is over 2,500 miles (4,000 km) long.
With its source Lake Itasca, in Itasca State Park in northern Minnesota, it is joined by the Missouri and Meramec River at Saint Louis, and by the Ohio at Cairo, Illinois. The Mississippi drains most of the area between the Rocky Mountains and the Appalachian Mountains, except for the area drained by the Great Lakes.
The Mississippi runs through, or borders, ten states in the United States -- Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Arkansas, Tennessee, Mississippi and Louisiana -- before emptying into the Gulf of Mexico about 100 miles (160 km) downstream from New Orleans.
The mouth of the river has shifted repeatedly over time. Since a canal was built in the early nineteenth century, the river has been seeking the Atchafalaya River mouth, some 60 miles (95 km) from New Orleans. The U.S. Army Corps of Engineers maintains a massive system of locks to keep the river in its present course.
Other changes in the course of the river have occurred because of earthquakes along the New Madrid Fault Zone, which lies near the cities of Memphis and St. Louis. Three earthquakes in 1811 and 1812, estimated at approximately 8 on the Richter Scale, were said to have temporarily reversed the course of the Mississippi. These earthquakes also created Reelfoot Lake in Tennessee from the altered landscape near the river.
On May 8, 1541 Hernando de Soto became the first recorded white man to reach the Mississippi River (he named it Rio de Espiritu Santo). Louis Joliet and Jacques Marquette began exploring the Mississippi on May 17, 1673.
The river was noted for the number of bandits which called its islands and shores home, including John Murrell who was a well-known murderer, horse stealer and slave "re-trader." His notoriety was such that author Mark Twain devoted an entire chapter to him in his book Life on the Mississippi, and Murrell was rumored to have an island headquarters on the river at Island 37.
Twain's book also extensively covered the thrilling steamboat races which took place from 1830 to 1870 on the river before more modern boating methods replaced the steamer. It was published first in serial form in Harper's Weekly in seven parts in 1875 and was intended to chronicle the rapidly disappearing steamboat culture. The full version, including a passage from the unfinished Huckleberry Finn and works from other authors, was published by James R. Osgood & Co in 1885. The first steamboat to travel the full length of the Mississippi from the Ohio River to the city of New Orleans, Louisiana was the New Orleans in December 1811. Its maiden voyage occurred during the series of New Madrid earthquakes in 1811-1812.