Nigeria is a country in West Africa, formally the Federal Republic of Nigeria. It is Africa’s most populous country, with 923,769 square kilometers (356,669 square miles) of land between the Sahel and the Gulf of Guinea in the Atlantic Ocean. It is bordered on the north by Niger, the northeast by Chad, the east by Cameroon, and the west by Benin. Nigeria is a federal republic made up of 36 states and the Federal Capital Territory, which is home to the country’s capital, Abuja. Lagos, Nigeria’s largest city and the second-largest in Africa, is one of the world’s most populous metropolises.