Niger River Niger River The Niger River (; , ) is the principal river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in southeastern Guinea. It runs in a crescent through Mali, Niger, on the border with Benin and then through Nigeria, discharging through a massive delta, known as the Niger Delta or the Oil Rivers, into the Gulf of Guinea in the Atlantic Ocean. The Niger is the third-longest river in Africa, exceeded only by the Nile and the Congo River (also known as the Zaïre River). Its main tributary
Flooding of the Nile August causing enormous precipitations on the Ethiopian Highlands whose summits reach heights of up to 4550 m (14,928 ft). Most of this rainwater is taken by the Blue Nile and by the Atbarah River into the Nile, while a less important amount flows through the Sobat and the White Nile into the Nile. During this short period, those rivers contribute up to ninety percent of the water of the Nile and most of the sedimentation carried by it, but after the rainy season, dwindle to minor rivers. These facts were unknown to the ancient Egyptians who could only observe the