The Iya (Russian: И́я) is a river in Irkutsk Oblast in Russia. The river is 484 kilometres long, and its basin covers 18,100 square kilometres . The Iya flows into the Okinsky Bay of the Bratsk Reservoir. The river freezes up in late October or early November and stays icebound until late April or early May. The town Tulun lies on the Iya. Its main tributaries are the Kirey, Ikey and Ilir.
