The Serpentine River is a river in the South West region of Western Australia. The river rises in the Darling Scarp below Bowerling Hill and flows westward crossing Albany Highway North of North Bannister. The river continues North West through the Youarling State Forest then the Serpentine National Park. The river flows through Serpentine Dam then flows over Serpentine falls just south of Jarrahdale as it comes off the Scarp and onto the Swan Coastal Plain. The river continues West and crosses the South Western Highway then flows past the town of Serpentine. The river then veers South and continues until it discharges into the Peel Inlet near Mandurah, Western Australia.