Lena (lēˈnə, Rus. lyĕˈnə) [key], river, easternmost of the great rivers of Siberia, c.2,670 mi (4,300 km) long, rising near Lake Baykal, SE Siberian Russia. It flows northeast, then north along the east side of the central Siberian uplands and parallels the Verkhoyansk Range, reaching a width of 8.5 mi (13.7 km). It empties through a c.250-mi- (400-km-) wide delta into the Arctic Ocean. It is navigable for 2,135 mi (3,436 km) upstream; at Yakutsk (915 mi/1,473 km upstream) it is ice free from June to October; at the delta from July to September. Coal and gold are found along the Lena and its tributaries (the Vitim and the Aldan). The Lena was first reached by the Russians in 1630.