Two great areas of Africa are virtually empty: the vast Sahara desert, larger than the United States, and the desert and semi-desert regions of the south-west. Elsewhere, the population is very unevenly distributed. Thinly peopled zones with less than ten people per square mile separate the five main concentrations of population, which are: West Africa, north of the Gulf of Guinea (60 million people, over 35 million of them in Nigeria); the north-western coastal belt along the Mediterranean (26 million); the valley of the Nile (30 million); the eastern highlands, especially around the great lakes and the sources of the Nile (30 million); the eastern half of South Africa and neighbouring areas (20 million).
Population increase is now rapid, and probably two-fifths of the whole population are under 15 years of age. By the end of the century Africa's population, now reckoned at between 240 and 250 million, may have doubled itself, and reached the 500 million mark. If present trends continue, this increase will make for still more uneven distribution; growth is greatest in areas that are already well populated, and the modern cities founded by Europeans are drawing in more people. There are few ancient cities in the interior; the Yoruba (C, 20) of western Nigeria have the only strong urban tradition found outside the Moslem lands of the north.
European settlement has mostly been concentrated in areas where white men have found the climate favourable and good conditions for raising commercial crops: in Algeria in the north, South Africa and the Rhodesias in the south, the highlands of Kenya and the Congo in the east. The other large immigrant community is of Indian origin, and is found in eastern Africa from Kenya and Uganda southward to Natal (D).