Federal Republic of Nigeria, is a federal constitutional republic comprising thirty-six states and one Federal Capital Territory. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in the north. Its coast lies on the Gulf of Guinea, a part of the Atlantic Ocean, in the south. The capital city is Abuja. The three largest and most influential ethnic groups in Nigeria are the Hausa, Igbo and Yoruba.
The people of Nigeria have an extensive history, and archaeological evidence shows that human habitation of the area dates back to at least 9000 BCE. The Benue-Cross River area is thought to be the original homeland of the Bantu migrants who spread across most of central and southern Africa in waves between the 1st millennium BCE and the 2nd millennium CE.
The name Nigeria was created from a portmanteau of the words Niger and Area, taken from the River Niger running through Nigeria. This name was coined by the future wife of the Baron Lugard, a British colonial administrator, during the early 20th century.
Nigeria is the most populous country in Africa and the eighth most populous country in the world with a population of over 140 million, therefore making it the most populous 'black' country in the world. It is a regional power, is listed among the "Next Eleven" economies, and is a member of the Commonwealth of Nations. The economy of Nigeria is one of the fastest growing in the world with the International Monetary Fund projecting a growth of 9% in 2008 and 8.3% in 2009.
Nigeria is located in western Africa on the Gulf of Guinea and has a total area of 923,768 km² (356,669 mi²),making it the world's 32nd-largest country (after Tanzania). It is comparable in size to Venezuela, and is about twice the size of California. It shares a 4047 km (2515-mile) border with Benin (773 km), Niger (1497 km), Chad (87 km), Cameroon (1690 km), and has a coastline of at least 853 km.
Nigeria has a varied landscape. From the Obudu Hills in the southeast through the beaches in the south, the rainforest, the Lagos estuary and savannah in the middle and southwest of the country and the Sahel to the encroaching Sahara in the extreme north. The highest point in Nigeria is Chappal Waddi at 2,419 m (7,936 ft).
Nigeria's main rivers are the Niger and the Benue which converge and empty into the Niger Delta, the world's largest river deltas.
Nigeria is also an important centre for biodiversity. It is widely believed that the areas surrounding Calabar, Cross River State, contain the world's largest diversity of butterflies. The drill monkey is only found in the wild in Southeast Nigeria and neighboring Cameroon.
Nigeria's most expansive topographical region is that of the valleys of the Niger and Benue River valleys (which merge into each other and form a "y" shape). Plains rise to the north of the valleys. To the southwest of the Niger there is "rugged" highland, and to the southeast of the Benue hills and mountains are found all the way to the border with Cameroon. Coastal plains are found in both the southwest and the southeast.
When dividing Nigeria by climatic regions, three regions, the far south, the far north, and the rest of the country emerge. The far south is defined by its tropical rainforest climate, where annual rainfall is 60 to 80 inches a year. The far north is defined by its almost desert-like climate, where rain is less than 20 inches per year. The rest of the country, everything in between the far south and the far north, is savannah, and rainfall is between 20 and 60 inches per year.
Nigeria is covered by three types of vegetation: forests (where there is significant tree cover), savannah (insignificant tree cover, with grasses and flowers located between trees), and montane land. (The latter is the least common, and is mainly found in the mountains near the Cameroonian border.) Both the forest zone and the savannah zone are divided into three parts.
The forest zone's most southerly portion is defined as salt water swamp, also known as a mangrove swamp due to the large amount of mangroves in the area. North of this is fresh water swamp, containing different vegetation from the salt water swamp, and north of that is rain forest.The savannah zone's three categories are divided into "Guinea savannah," the most common across the country, "Sudan savannah," and "Sahel savannah." Guinea savannah is made up of plains of tall grass which are interrupted by trees; Sudan savannah is similar but with "shorter grasses and shorter trees." Sahel savannah is comprised patches of grass and sand, and is found in the northeast.