The Aniak River is a 95-mile (153 km) tributary of the Kuskokwim River in the U.S. state of Alaska. Beginning south of Aniak Lake, the river generally flows north. The upper sections drain part of the Kilbuck and Kuskokwim mountains, and the lower portions transition to the Kuskokwim lowlands and tundra. The river empties into the Kuskokwim River slightly east of Aniak.Aniak is a Yup'ik word meaning "the place where it comes out," which refers to the mouth of the Aniak River.