river and tributary of the Lena River in eastern Siberia, Russia. It rises on the eastern slopes of the Ikat Mountains near the town of Bagdarin in Buryatiya and flows in a generally northerly direction to join the Lena in a delta at the town of Vitim. It has a length of 1,229 mi (1,978 km), and the area of its basin is 87,650 sq mi (227,000 sq km). The Vitim is navigable to the town of Bodaybo, the centre of the Bodaybo goldfields, located 185 mi from its mouth.