The Petit-Rhône is an arm of the Rhône delta which marks the administrative boundary between the Provence-Alpes-Côte d'Azur and Occitanie regions, between the departments of Bouches-du-Rhône (13) and Gard (30) and a more symbolic way between the Gard Camargue and the Grande Camargue. It separates from the Grand-Rhône north of Arles to join the Mediterranean Sea near Saintes-Maries-de-la-Mer.