Religious affiliation in Nigeria is strongly related to ethnicity, with rather distinct regional divisions between ethnic groups. The northern states, dominated by the Hausa and Fulani groups, are predominantly Muslim while the southern ethnic groups have a large number of Christians. In the southwest, there is no predominant religion.
Nigeria is a federal republic modeled after the United States, with executive power exercised by the president. The government of Nigeria is also influenced by the Westminster System model in the composition and management of the upper and lower houses of a bicameral legislature.
About two-thirds of Nigeria lies in the watershed of the Niger River, which empties in to the Atlantic at the Niger Delta, and its major tributaries: the Benue in the northeast, the Kaduna in the west, the Sokoto in the northwest, and the Anambra in the southeast.