The Onon River is a significant waterway located in northeastern Mongolia. It flows for approximately 818 kilometers and is a tributary of the Shilka River, which eventually joins the Amur River. The river is known for its scenic landscapes and is an important resource for local wildlife and communities. The Onon River is historically notable as it runs through the region associated with the life of Genghis Khan. The river's basin supports various ecosystems and is vital for agriculture and fishing in the area. Its waters are also used for irrigation, contributing to the livelihoods of nearby residents.