In geography, a confluence (also: conflux) occurs where two or more watercourses join to form a single channel.[1] A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); or where two streams meet to become the source of a river of a new name (such as the confluence of the Monongahela and Allegheny rivers, forming the Ohio River); or where two separated channels of a river (forming a river island) rejoin at the downstream end. The point of confluence where the channel flows into a larger body of water may be called the river mouth.