Which river system drains much of western Africa southward?

The Niger River system is the principal river system of western Africa and the largest river basin in the region.12

While the Niger River follows a complex path—initially flowing northeastward through Mali before turning southeast and eventually south through Nigeria—it is the primary system that drains much of western Africa southward into the Gulf of Guinea via its massive delta. The system, which includes major tributaries such as the Benue River, drains a total area of approximately 730,000 square miles.31

It is important to note that while the Niger is the largest basin in the region, other rivers in western Africa, such as those originating in the Fouta Djallon highlands, flow in various directions, including westward or northward, depending on their specific geography.34