Mitidja, (Arabic: متيجة, Berber: Mettijet ⵎⴻⵜⵙⵉⵛⵝ) is a plain stretching along the outskirts of Algiers in northern Algeria.

The Mitidja plain is bounded on the east by the Boudouaou River, on the west by the Nador River, on the north by the hills of the Algiers Sahel, and on the south by the Blidean Atlas [fr] range.

[1] Its fertile soils enjoy a temperate Mediterranean climate with adequate rainfall,[1] and are devoted largely to the cultivation of citrus fruits in east and grapes in the west.

[1] From west to east, the plain traverses the wilayas (provinces) of Tipaza, Blida, Algiers, Boumerdès, and the north-eastern corner of Médéa.

Four important urban centers are located along its edges: Algiers to the north, Blida to the south, Boumerdès to the east and Tipaza to the west, while Boufarik occupies the centre of the plain itself.