Mu River is a river in upper central Myanmar (Burma), and a tributary of the country's chief river, the Irrawaddy. It drains the Kabaw valley and part of the Dry Zone between the Ayeyarwady to the east and its largest tributary the Chindwin River to the west. It flows directly north to south for about 275 km (171 mi) and enters the Ayeyarwady west of Sagaing near Myinmu.