This Multiparty government transitioned from military to civilian rule. Also Nigeria is one-third larger than Texas and the most populous country in Africa, is situated on the Gulf of Guinea in West Africa. Its neighbors are Benin, Niger, Cameroon, and Chad. The lower course of the Niger River flows south through the western part of the country into the Gulf of Guinea. Swamps and mangrove forests border the southern coast inland are hardwood forests. The first inhabitants of what is now Nigeria were thought to have been the Nok people (500 BC –c. AD 200). The Kanuri, Hausa, and Fulani peoples subsequently migrated there. Islam was introduced in the 13th century, and the empire of Kanem controlled the area from the end of the 11th century to the 14th.

The Fulani empire ruled the region from the beginning of the 19th century until the British annexed Lagos in 1851 and seized control of the rest of the region by 1886. It formally became the Colony and Protectorate of Nigeria in 1914. During World War I, native troops of the West African frontier force joined with French forces to defeat the German garrison in Cameroon.

Nigeria’s stability has been repeatedly threatened by fighting between fundamentalist Muslims and Christians over the spread of Islamic law (sharia) across the heavily Muslim north. One-third of Nigeria’s 36 states is ruled by sharia law. More than 10,000 people have died in religious clashes since military rule ended in 1999.

In 2003, after religious and political leaders in the Kano region banned polio immunization—contending that it sterilized girls and spread HIV—an outbreak of polio spread through Nigeria, entering neighboring countries the following year. The Kano region lifted its ten-month ban against vaccination in July 2004. On Aug. 24, there were 602 polio cases worldwide, 79% of which were in Nigeria.

Since 2004, insurgency has wreaked havoc in the Niger delta, Nigeria’s oil-producing region. The desperately impoverished local residents of the delta have seen little benefit from Nigeria’s vast oil riches, and rebel groups are fighting for a more equal distribution of the wealth as well as greater regional autonomy. Violence by rebel groups has disrupted oil production and reduced output by about 20%. Nigeria is one of the world’s largest oil producers and supplies the U.S. with one-fifth of its oil. In August, 2006 Nigeria handed over the oil-rich Bakassi peninsula to Cameroon, in compliance with a 2002 World Court ruling.