a river in the Evenki National Okrug and the Taimyr (Dolgano-Nenets) National Okrug, Krasnoiarsk Krai, RSFSR. A right tributary of the Khatanga River (in the basin of the Laptev Sea). Length, 1,409 km; basin area, 176,000 sq. km. The Kotui takes its source in the Putorana Plateau and flows southeast along the Central Siberian Plateau, passing Lakes Kharpicha and Diupkun. After the influx of the Voevolikhan River from the right, the Kotui turns northeastward. In its lower reaches, it flows through the North Siberian Lowland.
The Kotui meanders in places and has many rapids. The river is fed by a mixture of sources, with snow predominating. It freezes over in late September or the first half of October and opens up in late May or June. Its principal tributaries are the Moiero, Kotuikan, and Eriechka on the right and the Changada and Tukalan on the left.