Chad 24°E. Chad is bounded to the north by Libya, to the east by Sudan, to the west by Niger, Nigeria and Cameroon, and to the south by the Central African Republic. The country's capital is from the nearest seaport, Douala, Cameroon. Because of this distance from the sea and the country's largely desert climate, Chad is sometimes referred to as the "Dead Heart of Africa". The dominant physical structure is a wide basin bounded to the north and east by the Ennedi Plateau and Tibesti Mountains, which include Emi Koussi, a dormant volcano that reaches above sea level. Lake Chad,
Nigeria (), Niger (), Chad (), Cameroon (), and has a coastline of at least s. Nigeria lies between latitudes 4° and 14°N, and longitudes 2° and 15°E. The highest point in Nigeria is Chappal Waddi at . The main rivers are the Niger and the Benue, which converge and empty into the Niger Delta. This is one of the world's largest river deltas, and the location of a large area of Central African mangroves. Nigeria has a varied landscape. The far south is defined by its tropical rainforest climate, where annual rainfall is a year. In the southeast stands the