The Main (maɪn) is a river in Germany, 524 km (329 miles) long (including White Main, 574 km (357 mi)), and it is one of the more significant tributaries of the Rhine. The Main flows through the German states of Bavaria, Baden-Württemberg (forming the border with Bavaria for some distance) and Hesse. Its watershed competes with the Danube for water; as a result, many of its boundaries are identical with those of the European Watershed. The Main rises near Kulmbach at the joining of its two headstreams, the Red Main and the White Main. The Red Main rises in the Frankish Alb, 50 km (30 mi) in length, and runs through Creussen and Bayreuth. The White Main rises in the mountains of the Fichtelgebirge; it is 41 km (25 mi) long. Major tributaries of the Main are the Regnitz, the Fränkische Saale, the Tauber, and the Nidda.
Around Frankfurt are several large inland ports. Because the river is rather narrow on many of the upper reaches, navigation with larger vessels and push convoys requires great skill.
The largest city along the Main is Frankfurt am Main. After the junction of its headstreams, the Main passes the following towns and cities: Burgkunstadt, Lichtenfels, Staffelstein, Eltmann, Haßfurt, Schweinfurt, Volkach, Kitzingen, Marktbreit, Ochsenfurt, Würzburg, Karlstadt, Gemünden, Lohr, Marktheidenfeld, Wertheim am Main, Miltenberg, Obernburg, Aschaffenburg, Seligenstadt, Hainburg, Hanau, Offenbach, Frankfurt, Hattersheim, Flörsheim, and Rüsselsheim.