Built as a fortress in 1524, on the orders of King Francis I it later became a prison. It is located on the island of If, the smallest island in the Frioul Archipelago, about a mile offshore in the Bay of Marseille.

The château is a square building, flanked by three towers with large gun embrasures. Its construction raised many controversies, and in 1481, when Marseille was annexed to France, it retained the right to provide for its own defense. So, the castle was seen as an unwanted imposition of central authority.

Chateau d'If became famous world wide after it became the main setting of Alexandre Dumas' novel "The Count of Monte Cristo".