Nigeria, republic in western Africa, with a coast along the Atlantic Ocean on the Gulf of Guinea. Most of Nigeria consists of a low plateau cut by rivers, especially the Niger and its largest tributary, the Benue. The country takes its name from its chief river. Until 1991, the capital was the largest city, Lagos, on the southwestern coast; at that time, the city of Abuja, in the country’s interior, became capital.

Nigeria is by far the most populated of Africa’s countries, with more than one-seventh of the continent’s people. The people belong to many different ethnic groups. These groups give the country a rich culture, but they also pose major challenges to nation building. Ethnic strife has plagued Nigeria since it gained independence in 1960.