Lengths of major rivers Lengths of the major rivers Take a look at a map of the United States or of any country in the world. This is no coincidence.
Rivers provide water for the essential needs of both tiny towns and huge cities.
There's a good chance that you live near one of our nation's large rivers. Look at the graphic below to see our short list of long rivers. Here, we define river length as the distance to the outflow point from the original headwaters where the name defines the complete length.