Iya River (Russian: Ия) is a river in Irkutsk Oblast in Russia. The length of the river is 486 km. The area of its basin is 18,100 km². The Iya flows into the Okinsky Bay of the Bratsk Reservoir. The river freezes up in late October - early November and stays icebound until late April - early May. Its main tributaries are the Kirey, Ikey, and Ilir Rivers.