Khentii Mountains
It originates at the eastern slope of the Khentii Mountains. For 298 km it flows within Mongolia, before entering the Dauria region of the Russian Far East. It joins with the Ingoda to produce the Shilka. Its river valley forms the eastern limit of the Khentei-Daur Highlands. Its main tributaries are the Khurkhyn Gol, Borzya and Unda from the right, and the Agutsa, Kyra and Aga from the left.