The western branch of the Liao Xiliao River is formed by the confluence of the Xar Moron River flowing from the east and the Laoha River flowing from the south, at approximately 43° 25' N, 120° 45' E. It is joined by the Xinkai He, which drains the southeast slopes of the Khingan Mountains and is dry in its upper reaches except after thunderstorms, 8 kilometres (5 mi) north of the city of Shuangliao. The eastern branch of the river (Dong Liao He) rises in low mountains in central Liaoning. The two branches of the river meet near the junction of Liaoning, Jilin and Inner Mongolia, approximately 42° 59' N, 123° 33' E, and flow across a vast plain to the Bohai Gulf.
Two major tributaries of the river, the Hun He ("muddy river") and the Taizi He, both of which flow down from the Qianshan range, used to flow into the Liao River shortly before it flowed into the sea, but the Atlas of China (Beijing, SinoMaps Press, 2006) shows that while the two tributaries continue to follow their traditional route and flow into the sea at what this atlas still identifies as the "Liao He Kou", the mouth of the Liao River, virtually all of the water of the Liao He has been diverted into the ShuangTaizi He, which flows into Bohai Gulf about 35 kilometres (22 mi) to the northwest. Google Earth also shows this new pattern.
Several major cities are located on the Hun He, including Shenyang, the provincial capital, Fushun, farther upstream, and Yingkou at the mouth. Anshan is located on the southeastern edge of the basin.
The Liao He drains an area of over 232,000 square kilometres (90,000 sq mi), but its mean discharge is quite small at only about 500 cubic metres per second (18,000 cu ft/s), about one-twentieth that of the Pearl River.
Like the Huang He, the Liao He has an exceedingly high sediment load because many parts of it flow through powdery loess.