The Nadym (Russian: Нады́м) is a river in Yamalo-Nenets Autonomous Okrug, Russia. It is a left tributary of the Ob River. The length of the Nadym River is 545 kilometers (339 mi). The area of its basin is 64,000 square kilometers (25,000 sq mi). The river originates in Lake Numto and flows into the Kara Sea. It freezes up in October and stays under the ice until late May. The Levaya Khetta River is one of the biggest tributaries of the Nadym River. The town of Nadym is located on the Nadym River. It is known for having a very rickety pontoon bridge for summer use while winter roads go over the ice.