Far North Region, Cameroon Logone rises west of the territory and flows north to form most of the border between the Far North and Chad. It eventually meets the Chari, which also rises in Chad. The Chari forms the remainder of the Chad-Cameroon border beginning at Kousséri before emptying into Lake Chad. These rivers all follow a tropical regime, fluctuating between high water in the wet season (May to September) and low water in the dry season (October to April). At the height of the dry season, many of the waterways disappear completely or else diminish to a mere trickle. The Logone all but
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