Those would be the Missouri and the Ohio rivers. The Mississippi river travels some 95 miles, starting in southern Minnesota, and meandering its way through over 31 states as it reaches its final destination below New Orleans, Lousiana, and empties into the Gulf of Mexico. The Missouri river is the Mississippi rivers largest tributary, followed by the Ohio river, both of which are major rivers in and of themselves. Improvements have been made to both those waterways in an effort to increase river traffic as related to business and economics. The Mississippi river itself has long been a major thoroughfare for economic and business development. The Mississippi serves as a servicing watershed for the aforementioned 31 states in the 48 contiguous United States. The Mississsippi river is the fourth largest river in the world, and the 10th most powerful river in the world.