It is a well-documented fact that early civilizations almost without exception were located along navigable river systems. Rivers were important not only for fresh drinking water but also for transportation of people and goods, communication and for moving armies during warfare.
Rivers were also used for exploring the heart of continents once the coast area had been settled. There are five primary rivers in Africa. They are, the Nile in the northeast, the Congo on the west coast flowing through the Congo Rain Forest and emptying into the Gulf of Guinea, the Zambezi River flowing from south central Africa through Mozambique and emptying into the Mozambique Channel, the Niger River in northwestern Africa, and the Orange River in the very southwestern point of Africa.
These rivers do provide drinking water however there is a major difference between these rivers and those of say North and South America. The rivers in Africa only flow a few miles inland before waterfalls and cataracts of significant size are encountered. The Nile is the one exception flowing hundreds of miles before significant falls bring ships to a halt.