The Dokog River in the west and the Markog River in the east both flow southeasterly from the Bayan Har Mountains in Qinghai and into Sichuan Province. The two stems meet in Aba Prefecture, and continue south as the Dajin Chuan (). Here, the river flows between the Daxue Mountains to the west and the Qionglai Mountains to the east. In Danba County, the Dajin Chuan meets the Xioajin Chuan () and together become the Dadu River in name. The Dadu continues south through Luding until it turns east at Shimian. East of Hanyuan, the Dadu enters the Dadu River Canyon () before reaching the lowlands of the Sichuan Basin just below Mount Emei.