Sayan Mountains (säyän`), central Asia, chiefly in S Siberia. The Eastern Sayan Mts. extend c.680 mi (1,090 km) from the lower Yenisei River to the southwest end of Lake Baykal and rise to 11,686 ft (3,562 m) in the Munku-Sardyk; they form part of the Russian-Mongolian border. The Western Sayan Mts., rising to 10,206 ft (3,111 m) in the Kyzyl-Tayga, extend c.400 mi (640 km) NE from the Altai range to the central section of the Eastern Sayan Mts. There are a variety of mineral deposits in the Sayan Mts. Lumbering, agriculture, and hunting are the chief occupations there.