Sahel zone (Wiki)

The Sahel is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna (historically known as the Sudan region) to the south. The Sahel part of Africa includes (from west to east) parts of northern Senegal, southern Mauritania, central Mali, northern Burkina Faso, the extreme south of Algeria, Niger, the extreme north of Nigeria, central Chad, central and southern Sudan, the extreme north of South Sudan, Eritrea, Cameroon, Central African Republic and extreme north of Ethiopia.