The Ilz (German: [ɪlt͡s]) is a river running through the Bavarian Forest, Germany. It is a left tributary of the Danube and 40 km (25 mi) in length (69 km (43 mi) including its main source river Große Ohe), during which it travels down a height difference of ~140m. The Ilz is formed at the confluence of its source rivers Große Ohe and Kleine Ohe in Eberhardsreuth. In the city of Passau it finally enters the Danube. Another town on the Ilz is Fürsteneck.