Ket River (Russian: Кеть), also known in its upper reaches as the Big Ket River (Russian: Большая Кеть) is an east-flowing river in the Krasnoyarsk Krai and Tomsk Oblast in Russia, a right tributary of the Ob River. The Ket River is 1,621 kilometres (1,007 mi) long. The area of its basin is 94,200 square kilometres (36,400 sq mi). It freezes up in late October or early November and stays under the ice until late April or early May.