The Main is the longest tributary of the Rhine. It rises as the White Main in the Fichtel Mountains of northeastern Bavaria and flows west through central Germany for 525 kilometres (326 mi) to meet the Rhine below Rüsselsheim, Hesse. The cities of Mainz and Wiesbaden are close to the confluence.
The largest cities on the Main are Frankfurt am Main, Offenbach am Main and Würzburg. It is the longest river lying entirely in Germany (if the Weser-Werra are considered separate).