Created by the rise in water levels at the end of the Last Glacial Period (colloquially known as the last ice age), this small inland sea is composed of three parts: the principal body of water, the Étang de Vaïne to the east and the Étang de Bolmon to the south-east.

Two canals link it to the Mediterranean, the open air Canal de Caronte [fr] leading towards Port-de-Bouc and the Canal de Marseille au Rhône which leads towards L'Estaque through the Rove Tunnel; the Rove Tunnel has been closed since 1963, after a section of the tunnel collapsed.

The Marseille Provence Airport is located in the southeast portion of the Étang de Berre, with its main runway extending into the water on reclaimed land.

Ten communes border the Étang de Berre: Istres, Miramas, Saint-Chamas, Berre-l'Étang, Rognac, Vitrolles, Marignane, Châteauneuf-les-Martigues, Martigues and Saint-Mitre-les-Remparts.

The ancient name of the Étang de Berre was Stagnum Mastromela, according to Pliny the Elder (Book III [34]).