MAIN, MAINE, or MAYN (the ancient Manus), formed by the union in North Bavaria, about 14 miles N.W. of Bayreuth, of two streams, the Red and White Main, which have their sources in the Fichtelgebirge. It has a very irregular and winding course in a direction generally westerly, and falls into the Rhine nearly opposite to Mentz. It is about 280 miles in length, and is navigable as far as its junction with the Regnitz, near Bamberg, about 240 miles from its mouth. As early as 793 Charlemagne had projected the formation of a canal between the Altmühl and the Pegnitz, an affluent of the Regnitz, and so connecting the Main and the Danube; but it is only very recently that this has been effected. The chief tributaries of the Mayn are,—the Regnitz, Tauber, Mühlung, and Gersprenz from the S., the Rodach, Saale, Kinzig and Nidda from the N. The principal towns on or near its banks are Bayreuth, Bamberg, Würzburg, Aschaffenburg, Hanau, Offenbach, and Frankfurt.