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 992 kilometres (616 mi) or 1,024 kilometres (636 mi), according to other sources. The Selenga River is the headwaters of the Yenisei-Angara River system. Carrying 935 cubic metres per second (33,000 cu ft/s) of water into Lake Baikal, it comprises almost half of the riverine inflow and forms a wide delta of 680 square kilometres (260 sq mi), when it reaches the lake.