The first (pervasive) misconception is that Africa  is urbanising exceptionally fast due to intensive rural-urban migration. This is simply not true. Africa’s rate of urbanisation (i.e. change in the percentage of Africans living in urban as opposed to rural areas) is far lower than that of East Asia, for example, and not unusually rapid by historical standards. However, what is true is that Africa’s urban population has been growing at an historically unprecedented rate for decades. It is important from a policy perspective to appreciate this distinction between rates of urbanisation and rates of urban population growth. Most policy makers don’t.

Full post here, and check out Sean Fox excellent paper on the history of urbanization in Africa. From the abstract:

qualitative and quantitative evidence is used to explain the stylized facts of sub-Saharan Africa’s urban transition, namely the late onset of urbanization in Africa vis-à-vis other major world regions, the widely noted but inadequately explained phenomenon of ‘urbanization without growth’ observed in Africa in the 1980s and 1990s, and the historically unprecedented rates of urban population growth seen in the region throughout the late twentieth century.