The Crau is the ancient confluence of the Durance and Rhône, and constitutes their vast flat alluvial fan.
The Crau is composed of two different parts:
The dry Crau is in the south, and has been used as pasture from Roman times. There are around 100,000 sheep as of 2007[update],[citation needed] including the Merino sheep.
The wet Crau is in the north and includes the communes of Saint-Martin-de-Crau, Eyguières, Istres, Mouriès, and Arles. It produces the Crau hay, which benefits from an Appellation d’origine contrôlée
The Crau was described by Strabo as the Stony Plain (Book IV Chapter 1).