Longest U.S. Rivers on a Map - Easy

River: A body of water bearing the same name for its course

River system: A system which consists of at least two rivers. There are, however, requirements for this:

A river system has been assumed if it has

1. its source in a lake which is fed by a river of another name (e.g. Niagara River -> Lake Ontario -> St. Lawrence River)

2. its source at the confluence of two rivers, then following the longer one (e.g. Ohio -> Allegheny)

This in return means, that a longer tributary joining the main river later somewhere along its way is NOT considered a river system (e.g. Mississippi - Missouri)

N.B. I only considered information currently available in Wikipedia. The true length incl. small mountain headcreeks of unspecified length might be longer.

River length refers to total length (incl. course in Canada/Mexico)

All headwaters included can be found in quiz and answer stats.