The Sahara Desert’s extremely dry southern transition zone is called the Sahel.
The Sahel is a semiarid belt stretching across Africa immediately south of the Sahara. It runs broadly from the Atlantic coast toward the Red Sea, passing through countries including Senegal, Mauritania, Mali, Burkina Faso, Niger, Chad and Sudan.
The word Sahel comes from Arabic sāḥil, meaning “shore” or “coast.” In this context, it describes the southern “shore” or edge of the Sahara. Rainfall is higher than in the desert but strongly seasonal and variable from year to year.
The Sahel is not a sharp line on a map. Its vegetation and climate change gradually from desert conditions to grassland and savanna. Drought, land degradation and population pressure have made the region a major focus of environmental and development research.