The Château d'If is a fortress (later a prison) located on the island of If, the smallest island in the Frioul Archipelago situated in the Mediterranean Sea about a mile offshore in the Bay of Marseille in southeastern France. It is famous for being one of the settings of Alexandre Dumas' adventure novel The Count of Monte Cristo. The château is a square, three-story building 28 m long on each side, flanked by three towers with large gun embrasures.

• Telefoon +(0)4 91 59 02 30
• Adress 1 Quai de la Fraternité | Vieux Port - Ferry, 13007 Marseille - 7e Arrondissement
• Website https://www.marseilletourisme.fr/fr/que-voir/iles/iles-frioul/