The predominant racial group is West African Negroid. The purest lineage is now found in the southeastern forest belt, but Negroid stock forms the basic substratum throughout most of Nigeria. Non-Negroid racial types include the Fulani (Fulbe), of Mediterranean extraction, who are widely dispersed throughout the north but who have become largely assimilated to the predominant Negroid type, and the Semitic Shuwa Arabs, who are confined to the Lake Chad area in the extreme northeast.
There are three dominant ethnolinguistic groups. The Yoruba predominate in Ogun, Ondo, Oyo, and Osun states. The Ibo (Igbo) predominate in Anambra, Imo, Abia, and Enugu states. The Hausa and Fulani constitute the largest single groups in Sokoto, Kaduna, Jigawa, Katsina, and Kano states. Other important groups include the Kanuri in Borno and Yobe states; the Edo (Bini) in Edo State; the Ibibio in Akwa Ibam State; the Ijaw (Ijo) in Rivers State; the Tiv in Benue and Plateau states; and the Nupe in Niger State. The Hausa in the past have been officially estimated to constitute 21% of the population; Yoruba, 21%; Ibo, 18%; Fulani, 12%; Ijaw, 10%; Kanuri, 4.1%; Ibibio, 3.6%; Tiv, 2.5%; and others, 18.7%.