The third-longest African river is the Niger, which is 5 letters long. The Niger River is a major river in West Africa, extending about 4, 180 km (2, 600 mi) in length and passing through Guinea, Mali, Niger, Benin, and Nigeria. It is the third-longest river in Africa, after the Nile and the Congo. The Niger is the principal river of western Africa and is the primary source of water for much of the region. It is also an important source of food and transportation for the people living along its banks.