The Sahel region or Sahelian acacia savanna is a biogeographical region in Africa. It is the transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a hot semi-arid climate and stretches across the southernmost latitudes of North Africa between the Atlantic Ocean and the Red Sea. Although geographically located in the tropics, the Sahel does not have a tropical climate.

The Marrah Mountains or Marra Mountains are a range of volcanic peaks in a massif that rises up to 3,042 metres (9,980 ft). They are the highest mountains in Sudan.