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
Nile enormous swamps of the Sudd region of South Sudan. More than half of the Nile's water is lost in this swamp to evaporation and transpiration. The average flow rate of the White Nile at the tails of the swamps is about . From here it soon meets with the Sobat River at Malakal. On an annual basis, the White Nile upstream of Malakal contributes about fifteen percent of the total outflow of the Nile. The average flow of the White Nile at Lake Kawaki Malakal, just below the Sobat River, is ; the peak flow is approximately in October and