With its source in Minnesota, it is joined by the Missouri 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.
It runs through, or borders, a number of states in the United States, including Minnesota, Iowa, Illinois, Missouri, Tennessee, Mississippi, and Louisiana before emptying into the Gulf of Mexico a small distance 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 sixty miles from New Orleans. The U.S. Army Corps of Engineers maintains a massive system of locks to keep the river in its present course. (See <http://www.ce.utexas.edu/stu/mcbraymc/ce385proposal.html>)
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.
The word Mississippi comes from the Ojibway name for the river, "Messipi", which meant big river.