or WARTHA, a large river of Poland and Prussia, rises near the S.E. corner of Poland, 36 miles N.W. of Cracow. It flows in an irregular course through a flat country, at first towards the N. as far as Kolo in Poland, then turning westward, it enters the Prussian dominions, passes Posen, and falls into the Oder at Küstrin, after a course of about 420 miles. It receives from the right the Vidawka and the Netze, the latter connected by means of a canal with the Vistula; and from the left the Obra and the Prosa. The Warta is navigable for a considerable distance.