Aldan, river, c.1,400 mi (2,250 km) long, rising in the Stanovoy Range, Sakha Republic, SE Siberian Russia. It flows north and east, past Tommot and around the Aldan Plateau, before flowing generally northwest to enter the Lena River c.100 mi (160 km) N of Yakutsk. The Amga, Uchur, and Maya rivers are its main tributaries. The Aldan River is navigable c.1,000 mi (1,610 km) upstream. Gold is found in its basin.

Aldan (əldän´), city (1989 pop. 27,000), Sakha Republic, E Siberian Russia, on the Aldan Plateau. Located on a major north-south highway of the region, it is also in the heart of an important gold-mining area. Nearby, at Emeldzhak, are valuable mica deposits.