​ILLER, a river of Bavaria, rising in the south-west extremity of the kingdom, among the Algäuer Alps. Taking a northerly course, it quits the mountains at Immenstadt, and, flowing by Kempten, from which point it is navigable for rafts, forms for some distance the boundary between Bavaria and Württemberg, and eventually strikes the Danube (right bank) just above Ulm. Its total length is 103 m.