The Dadu River originates an the Bayan Har Mountains where Sichuan and Qinghai provinces meet. After the Lesser Jinchuan River converges with the Large Jinchuan in its upper reaches at Danba. it is called the Dadu River. The river rushes through high mountains and lofty ridges in the eastern part of the Hengduan Mountains. There are gorges with splendid scenery all the way, but it is in the Jinkou Gorge that the Dadu River gorge landscape reaches its climax. The Jinkou Gorge extends eastward for 26 kilometers from the WUSi River in Hanyuan County to the Jinkou River in Leshan City.

The valley floor is usually between 70 and 200 meters wide, shrinking at one point to below 50 meters; and the valley shoulders are about eight kilometers across at the widest point. At the exit of the canyon, the river valley is 580 meters above sea level at the lowest point, and Dawa Mountain on the northern bank of the Dadu River is 3,222 meters above sea level. making the canyon over 2,600 meters deep. Continuous, sheer and magnificent, the gorge is a rare and precious sight. The Jinkou Gorge is located on a dramatically rising section of the earth¡¯s crust in the eastern part of the Hengduan Mountains, moreover it is where the elevational difference between the first and second steps of China's "geological staircase" is greatest, and is predominantly composed of horizontally stratified hard dolomite.

These factors make it one of the most classical examples of a Zhang valley and ravine on China's large rivers, characterized by near vertical slopes, a deep and narrow floor almost completely taken up by the riverbed. The tributary channels feeding in on both sides are fathomless. narrow and precipitous beyond description. The entrance to the Jinkou Gorge has an unusual three-way access: running parallel to the Dadu River are the Jinkou-Wusihe Road and Chengdu-Kunming Railway, and winding through the perilous mountains is the Leshan-Xichang Road built during the Second World War.