The Selengе or Selenga (Mongolian: Сэлэнгэ, Russian: Селенга́) is a river in Mongolia and Russia. It rises in the Hangai Mountains under the name of Ider, and flows into Lake Baikal. Its length is 1024 km. The Selenge is the headwater of the Yenisei-Angara River.
It is then split into many waterways that used to form the river delta joining the Aral Sea, passing Urgench, Dashoguz and other cities, but it does not reach what is left of the sea anymore and is lost in the desert.
Historical records state that in different periods the river flowed into the Aral Sea (from the south), the Caspian Sea (from the east) or both, similar to the Syr Darya (Jaxartes, in Ancient Greek).
Rivers of Uzbekistan Syr Darya (also known as Syrdarya or Sirdaryo) is a river in Central Asia.