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
Sobat River its name. The Sobat and its tributaries drain a watershed approximately in size. The river's mean annual discharge is 412 m³/s (14,550 ft³/s). Sobat River The Sobat River is a river of the Greater Upper Nile region in northeastern South Sudan, Africa. It is the most southerly of the great eastern tributaries of the White Nile, before the confluence with the Blue Nile. The Sobat River is formed by the confluence of the west-flowing Baro River and the north-flowing Pibor River, on the border with Ethiopia. The river enters the White Nile at Doleib Hill, near the city of Malakal