The Selenga River (Selenge River, Mongolian: Сэлэнгэ мөрөн, Selenge mörön; Buryat: Сэлэнгэ гол, Selenge gol, Сэлэнгэ мүрэн, Selenge müren; Russian: Селенга́) is a major river in Mongolia and Buryatia, Russia. Its source rivers are the Ider River and the Delgermörön river. It flows into Lake Baikal and has a length of 616 miles (992 km) (1024 km according to other sources). The Selenga River is the headwaters of the Yenisei-Angara River system. It carries 935 m³/s of water into Lake Baikal which comprises almost half of riverine inflow and forms a wide delta when it reaches the lake (680 km²).
The name derives from Evenkisele 'iron' + -nga (suffix).Selenge Province in northern Mongolia is derived from the name of this river. The Mongolian verb "sele-" means swim.
The Selenga River in Russia
Railway bridge over the Selenga River outside of Ulan Ude, Russia.