Which Saharan dune field is the largest in Algeria?

The Grand Erg Oriental is the largest Saharan dune field in Algeria.

An erg is a broad region dominated by wind-blown sand, often containing immense fields of dunes. The Grand Erg Oriental, or Great Eastern Erg, occupies a large area of northeastern Algeria and extends toward Tunisia. Its dunes form part of the Sahara’s extensive sand-sea system rather than a single isolated ridge.

The erg’s shape and movement have been produced by prevailing winds, the availability of loose sediment, and the basin-like geography of the northern Sahara. Dune forms vary, and some individual dunes can rise many tens of metres above the surrounding surface. Roads and settlements generally skirt or cross the margins because moving sand makes travel difficult.

The Grand Erg Occidental is another major Algerian sand sea, but it lies farther west and is smaller. “Erg” describes a sand-dominated landscape; it does not mean every part of the Sahara is covered by dunes.