Erg (landform) and western Asia, and Central Australia. In South America, ergs are limited by the Andes Mountains, but they do contain extremely large dunes in coastal Peru and northwestern Argentina. They are also found in several parts of the northeast coast of Brazil. The only active erg in North America is in the Gran Desierto de Altar () that extends from the Sonoran Desert in the northwestern Mexican state of Sonora to the Yuma Desert of Arizona and the Algodones Dunes of southeastern California. An erg that has been fixed by vegetation forms the Nebraska Sandhills (). Sand seas and dune
Erg Ferradj are generally well provided for. 100% of Erg Ferradj's population is connected to drinking water, 99% is connected to the sewerage system, and 99% (including 756 buildings) have access to electricity. There is no fuel service station in the town. Erg Ferradj has a total of 1,300 houses, of which 712 are occupied, giving an occupation rate of 6.2 inhabitants per occupied building. Erg Ferradj is reached by a local road from the N6 highway just west of Abadla. It is from Abadla and from Béchar. There is a total length of of roads in the commune. There are 3