Oder, The, a river of Germany, rising in the Odergebirge, Moravia, 14 miles E. of Olmutz, and emptying itself into the Baltic Sea at Swinemiinde after a course of 550 miles. Passing with a sharp fall through Moravia, and dividing Prussian from Austrian Silesia, it meanders for 490 miles, through Silesia, Brandenburg, and Pomerania, in a sluggish and shallow stream, till it loses itself in the lagoon known as the Stettiner Haf, thence finding its way to the sea by three channels, of which the Swine is the chief. The principal tributaries are the Oppa, the two Neisses, the Katzbach, and the Bober on the west, and the Malapane, Bartsch, and Warthe on the east. Besides Swinemiinde the towns of Ratibor, Oppeln, Brieg, Breslau, Glogau, Frankfort, Custrin, and Stettin are on its banks. Navigable for seagoing craft as far as Stettin, it is with some difficulty kept open for barges and river-steamers up to Oderberg, and much traffic passes up and down. Canals connect it with the Havel, the Spree, and other rivers.