West Africa

West Africa preserves some of the earliest and most continuous evidence for human occupation in the western half of the continent, with archaeological traces extending back at least 15,000 years and likely much earlier. Stone tools and a partial cranium from the Iwo Eleru rock shelter in Nigeria, dated to roughly 13,000 years ago, represent some of the few Pleistocene fossils recovered in the region, while Middle and Later Stone Age assemblages in Senegal and Ghana indicate repeated occupation by hunter-gatherers adapted to savanna and forest margins. These finds remain sparse because of preservation challenges in tropical soils, leaving open questions about whether earlier Homo sapiens populations reached the area during the main dispersal out of eastern and southern Africa.

By the middle Holocene, population movements and technological shifts become clearer in the archaeological record. The emergence of settled communities practicing pearl millet cultivation appears in the Sahel by at least 2500 BCE, documented at sites such as Dhar Tichitt in Mauritania and later at Jenné-jeno in Mali. Linguistic evidence for the deep diversification of Niger-Congo languages aligns with these developments, suggesting that early West African farmers and herders expanded southward into forested zones. Some researchers argue that these expansions involved both cultural diffusion and demic movement, though the relative contributions remain difficult to quantify without more ancient genomes.

Major Iron Age societies left distinctive material signatures that illuminate social complexity predating external contact. The Nok culture of central Nigeria, flourishing between approximately 1500 BCE and 500 CE, produced large-scale terracotta figures and evidence of iron smelting at sites such as Taruga. Further east, the Igbo-Ukwu burials in southeastern Nigeria, dated to the ninth century CE, reveal sophisticated bronze casting and long-distance trade networks reaching the Sahara. These centers, together with the later Sahelian empires of Ghana, Mali, and Songhai, demonstrate that West Africa hosted indigenous processes of urbanization, state formation, and metallurgical innovation independent of Mediterranean or Near Eastern influence.

Ancient DNA studies have only recently begun to clarify the biological history of these populations. Limited preservation has restricted sampling, yet genomes from mid-Holocene individuals in present-day Cameroon and Senegal reveal deeply diverged West African lineages that contributed substantially to later Bantu-speaking expansions and to the ancestry of many contemporary West Africans. Ongoing work by teams including those led by researchers at the Max Planck Institute and Harvard University continues to test whether multiple distinct forager groups persisted alongside incoming farmers, a question that remains unresolved given the small number of sequenced individuals.

Beyond its deep-time significance, West Africa played a pivotal role in the transatlantic slave trade, with the majority of Africans forcibly transported to the Americas originating from Senegambia to the Bight of Biafra. Genetic and historical records together show how centuries of internal migration, warfare, and trade shaped the region’s demographic landscape long before European arrival, underscoring West Africa’s enduring contribution to global human diversity and the formation of new societies across the Atlantic.