ILLER, a river of Bavaria, rising in the south-west extremity of the kingdom, among the Algauer Alps.
The Danube, joined by the Iller just above the town and by the Blau just below, here becomes navigable, so that Ulm occupies the important commercial position of a terminal river-port.
The country mainly belongs to the basins of the Danube and the Main; by far the greater portion being drained by the former river, which, entering from Swabia as a navigable stream, traverses the entire breadth of the kingdom, with a winding course of 200 m., and receives in its passage the Iller, the Lech, the Isar and the Inn from the south, and the Naab, the Altmuhl and the WBrnitz from the north.
To the south of the Rauhe Alb the plateau of Upper Swabia stretches to the lake of Constance and eastwards across the Iller into Bavaria.
Just above Ulm it is joined by the Iller, which forms the boundary between Bavaria and Wurttemberg for about 35 m.