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 "seleh" means to swim.
The Selenga River in Russia
Railway bridge over the Selenga River outside of Ulan Ude, Russia.