The transition zone between desert and savanna in Africa is the Sahel.
The Sahel is a broad climatic and ecological belt along the southern edge of the Sahara. It separates the extremely dry Sahara Desert to the north from the more humid Sudanian savannas to the south. Because it lies between these environments, rainfall, vegetation, and land use change gradually across the region rather than stopping at a sharp natural boundary.
The name comes from the Arabic word sāḥil, meaning “shore” or “coast,” evoking the Sahel as the shore of the desert. It stretches roughly 5,900 kilometres from the Atlantic Ocean to the Red Sea. The region is mainly hot semi-arid, with a short rainy season and a long dry season. Drought, variable rainfall, population growth, farming, and grazing make the Sahel especially vulnerable to food and water insecurity. “Savannah” is a broader vegetation term, not the specific transition-region name.