In the past 50 years, West Africa has been experiencing intensive urbanization, which has affected the region’s largest and smallest urban centers (Cour and Snrech, 1998). In 1975, the distribution and pattern of West Africa’s settlements were little changed compared to their historical size and extent. These settlements — built up areas comprising human communities in a village, town, or city — were located near land most favorably suited to subsistence cereal farming and to the trans-Saharan trade routes, the region’s main source of wealth in the past (Moriconi-Ebrard, Harre, and Heinrigs, 2016). As a result, the Sudanian and Sahelian zones were relatively densely populated, especially the Peanut Basin of Senegal, the central plateau of Burkina Faso, and the Niger–Nigeria agricultural region. Other settlement zones were developed along the coasts of Côte d’Ivoire, Ghana, Togo, Benin, and Nigeria, as trade in gold and slaves, and eventually tropical products got under way (Cour and Snrech, 1998). Independence and the development of market economies, however, brought about a drastic change in the economic landscape, which influenced the settlement pattern of the region. New road networks in the region as well as the emergence of the industrial sector in the cities set in motion a massive shift in the West African population toward large urban areas (Moriconi-Ebrard, Harre, and Heinrigs, 2016).
Settlement growth is a useful proxy for analyzing population growth and population distribution. Land use maps show that settled or built-up areas increased by 140 percent in West Africa between 1975 and 2013 — to occupy 36,400 sq km by 2013 (0.7 percent of the land surface). The settlements distribution map (above) indicates both sprawl of existing urban centers (“top-down metropolisation”) and an increase in the number of small towns (“bottom-up urbanization”) (Beauchemin, 2005). Since 1975, settlements have expanded westward and southward—from the inland to the coast, but also from rural to urban areas, creating major secondary cities, especially across the Sahel.
In 1975, urban areas were confined mainly to the coast of the Gulf of Guinea. By 2013 West Africa’s settlements network had grown denser and expanded throughout the entire region, including the Sahara Desert where towns have sprung up across arid areas of Niger, Mali, Mauritania, and Chad despite an overall low population density in these countries. Across the region, numerous towns have grown into large urban centers or secondary towns like Bobo-Dioulasso (Burkina Faso), Bouaké (Côte d’Ivoire), Touba (Senegal), Kumasi (Ghana), and several large cities in Nigeria. The number of small agglomerations has also multiplied spectacularly across the region.
In the coastal countries, settlements sprawled around the main urban areas and their immediate hinterland. This dramatic coastal urban expansion is particularly visible from Accra (Ghana) to Lagos (Nigeria). In this coastal corridor, population has grown fast and population density is the highest in the West African region. With the exception of the small countries of The Gambia and Cabo Verde where settlements are concentrated in one large metropolis, the Gulf of Guinea countries are the most urbanized in the region, with settlements occupying between 1 percent (Benin) and 2 percent (Nigeria) of their national territory in 2013 (see graph). In the western part of the Atlantic coast, some areas remain relatively underpopulated and also under- urbanized. The prolonged political uprisings and conflicts in Liberia and Sierra Leone, as well as the Casamance conflict in Senegal, still hinder trade and the movement of people (Moriconi-Ebrard, Harre, and Heinrigs, 2016). During these conflicts, economic growth and infrastructure development were impeded, and part of the population migrated not only toward rural areas but also to neighboring countries (especially Guinea and Côte d’Ivoire). In the recent decade (2000–2013), settlements have greatly expanded along several axes perpendicular to the coastline — inwards from the coast, such as Dakar–Touba, Accra–Kumasi, or Lagos–Ibadan, and also following the major north-south routes, such as Maradi–Kano, and Abijdan–Ouagadougou. In the landlocked Sahel countries, large cities are sparser but new clusters and major regional hubs, such as Bamako and Ouagadougou, have emerged. Many new settlements also appeared along the major rivers in Senegal, Mali, Burkina Faso, Niger, and Chad. Because these countries have important agricultural resources to meet the growing demands of the regional market (cereals, fruits and vegetables, intensive livestock farming), the long east-west corridor from N’Djamena to Dakar constitutes a strategic area for regional trade and a very dynamic region for population flow and settlement in West Africa (Konseiga, 2005). Recent migration flows have been observed toward western Burkina Faso, a phenomenon that is accelerated by the success of cotton production and the urbanization of secondary cities, such as Bobo-Dioulasso.
Looking at each country individually, Mauritania and Burkina Faso stand out with the highest settlement growth rates, with an average of 23 and 7.7 percent per year, respectively. Mauritania’s high settlement growth rate can be explained by the very rapid urbanization of the capital Nouakchott following independence (see Nouakchott case study). In Burkina Faso also, the expansion of the capital Ouagadougou accounts for most of the country’s growth in urban population and settlement area. On the other hand, due to the conflicts they underwent, Sierra Leone and Liberia have the slowest average annual settlements growth rate over the past 40 years.
Current settlement patterns in West Africa are the result of various environmental, historical, and sociopolitical factors that have impacted each country individually and the region as a whole. West Africa will, for a long time to come, continue to experience strong population growth that will induce important intra-regional migration flows and rapid urbanization (Konseiga, 2005). However, recent (2000–2013) population growth, especially urban growth, has been slowing down. While cities are a necessity for economic development, they are not without numerous and daunting problems. Managing urban growth, including providing infrastructure and adequate services for an increasing number of citizens, must be considered a priority of public policy (Bossard, 2009).