Located in West Africa, Nigeria is the population giant of Africa, with more than 130 million people. The terrain changes from the oil-rich Niger Delta in the south to a belt of rain forests inland and to high savanna-covered plateaus in the north.

The population is as diverse as it is large, with some 250 ethnic groups. Nigeria's three largest ethnic groups are: Hausa-Fulani (29 percent of the population), Yoruba (21 percent) and Igbo, or Ibo (18 percent). Northern Nigeria is mostly Islamic and dominated by the Hausa-Fulani ethnic group. Southern Nigeria is more westernized and urbanized than the north, with the Yoruba in the southwest and the Igbo in the southeast. It is estimated that about half the Yorubas are Christian and half Muslim, though many maintain traditional beliefs. The Igbo in the southwest tend to be Christian; many are Roman Catholic.

A century of British rule ended in 1960. After independence ethnic tensions increased, deepened by the rift between the poor north and the more prosperous south. Civil war raged from 1967 to 1970, when the Igbo fought unsuccessfully for autonomy as the Republic of Biafra. The end of the civil war did not mark a return to political stability. After decades of military coups and military rule, free elections were held in 1999 that brought Nigeria back on the road to democracy. The system of government is based on the United States model with a federal government and 36 states, with a Federal Capital Territory at Abuja. The nation's capital moved from Lagos to Abuja in 1991. The federal form of government and location of the capital seek to balance the three major ethnic groups—and subdue ethnic and regional conflict. However, introduction of sharia (criminal code based in Islamic law) in 12 northern states in 2000 provoked violence between Christians and Muslims, leading to thousands of deaths.

Since the oil boom of the 1970s Nigeria has had an unhealthy dependence on crude oil. In 2002 oil and gas exports accounted for 98 percent of export earnings—providing 83 percent of the federal government's revenue. Agriculture suffers from years of mismanagement and corruption. The country's poor transportation infrastructure hinders economic development.