The most significant factor which accounts for the rapid growth in the population of the capital cities of West Africa is

Rural-urban migration is the most significant factor driving rapid population growth in the capital cities of West Africa. This is the large-scale movement of people from rural villages and towns to urban centres, particularly capital cities, in search of better employment, education, healthcare, and general living conditions.

West African capital cities such as Lagos (former capital of Nigeria), Accra, Dakar, and Abidjan have experienced explosive population growth primarily because of the continuous influx of rural dwellers. The "push" factors in rural areas include poverty, limited social amenities, lack of educational institutions, and poor infrastructure. The "pull" factors in cities include perceived job opportunities, better schools and hospitals, and modern amenities.

Political rallies, sport events, and religious tourism may temporarily increase the number of people in a city, but they do not cause permanent population growth. These are short-term gatherings after which attendees return to their places of origin. Rural-urban migration, by contrast, involves permanent or long-term relocation, which directly increases the resident population of the city.