What countries make up sachel region

The Sahel Region is the region that borders between the Sahara Desert to the North and Sudanian Savannah to the South. The countries which are known to traditionally make up the Sahel region are the Gambia, Senegal, Mauritania, Mali, Burkina Faso, Algeria, Niger, Nigeria, Cameroon, Chad, Sudan, South Sudan and Eritrea. Although the entirety of these countries are not considered all to fall within the Sahel Region.