The Sassandra River is a river of western Côte d'Ivoire in West Africa. It is formed by the confluence of the Tienba River, which originates in the highlands of northwestern Côte d'Ivoire, and the Gouan River (also known as the Bafing Sud River), which originates to the west in the highlands of Guinea. The Sassandra flows south-southeast to empty into the Gulf of Guinea on the Atlantic Ocean. The Buyo Dam was constructed across the middle stretch of the river in 1980, just below the confluence with the Nzo River, to create the reservoir called Lake Buyo. The Davo River joins the Sassandra just before it meets the sea.