Which North African mountain range forms much of the Sahara’s northern climatic boundary?

The Atlas Mountains form much of the Sahara’s northern climatic boundary.

The Atlas system stretches across Morocco, Algeria and Tunisia. Its ranges separate the Mediterranean-influenced north from the much drier Sahara to the south. Mountains intercept some moisture-bearing air, producing wetter conditions on certain northern slopes and a strong rain-shadow effect farther south.

The Atlas Mountains are not a single continuous ridge. They include several ranges, such as the High Atlas, Middle Atlas, Anti-Atlas, Tell Atlas and Saharan Atlas. Their highest summit is Toubkal in Morocco, at 4,167 metres.

The Sahara begins south of the Atlas system, but the transition is geographically complex. Some desert landscapes extend northward into mountain valleys and high plateaus, while semiarid steppe occupies areas between the mountains and the desert proper. This is why maps may show slightly different boundaries.