Geography of Chad lake has shrunk dramatically in the last four decades due to increased water usage from an expanding population and low rainfall. Bordered by Chad, Niger, Nigeria, and Cameroon, Lake Chad currently covers only 1350 square kilometers, down from 25,000 square kilometers in 1963. The Chari and Logone Rivers, both of which originate in the Central African Republic and flow northward, provide most of the surface water entering Lake Chad. Chad is also next to Niger. Located in north-central Africa, Chad stretches for about 1,800 kilometers from its northernmost point to its southern boundary. Except in the far northwest and south,
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