Baykal or Baikal (both: bīkäl´), lake, 12,160 sq mi (31,494 sq km), SE Siberian Russia. It is the largest freshwater lake of Eurasia, with a width up to 50 mi (80 km) and a length of c.395 mi (640 km), and it contains roughly a fifth of the world's fresh water. Its maximum depth is 5,714 ft (1,742 m), making Baykal the world's deepest lake. There are numerous feeder streams (notably the Selenga), but the only outlet is the Angara River, whose great volume is harnessed by several hydroelectric stations. Lake Baykal is navigable and is used to float timber. Surrounded by beautiful mountain scenery, it is rich in fish and other aquatic life, including such unusual species as the world's only freshwater seal. Although the lake is known for its crystal-clear waters, there is concern that industrial development in the area could lead to significant pollution. Plans to route a Siberian oil pipeline within .6 mi (1 km) of the lake provoked concern until President Putin called (2006) for the pipeline to be rerouted c.35 mi (40 km) to the north, outside the lake's watershed. The Trans-Siberian RR skirts the lake's southern shores. Between Lake Baykal and the upper Amur River lies the region known as Transbaykalia.

Baikal, Lake (Baykal) World's deepest lake in s Siberia, Russia; the largest freshwater feature in Asia. Fed by numerous small rivers, its outlet is the River Angara. Framed by mountains, Baikal has rich fish stocks and the world's only freshwater seal species. Its ecology is threatened by pollutants from lakeside factories, and government schemes have been introduced to protect the environment. Irkutsk lies on its n shore and the Trans-Siberian Railway runs along its s edge. Area: 31,494sq km (12,160sq mi). Max. depth: 1743m (5714ft).