The Imuruk Basin (Imaġruk in Iñupiaq) is an approximately 90 sq mi (230 km2), 17 mi (27 km) long shallow estuary located on the Seward Peninsula in the U.S. state of Alaska. The estuary's drainage basin covers about one quarter of the peninsula. The basin is fed by the Kuzitrin, Kruzgamepa, Agiapuk, and Cobblestone Rivers and is drained by the , which empties into Grantley Harbor (Pacific Ocean). The Imuruk Basin was a strategic waterway for early Iñupiat by providing accessibility to the Bering Sea from the Seward Peninsula's interior.