Fort San Juan may refer to:
Fort San Juan (Joara), established by Juan Pardo in 1567-8 as the earliest Spanish outpost in the interior of what is now North Carolina Fort San Juan (Nicaragua) Battle of Fort San Juan (1780), in which the fort in Nicaragua was contested San Juan de Ulúa, a fortress complex on an island overlooking Veracruz, Mexico Fortín San Juan de la Cruz (Fort Saint John of the Cross), or El Cañuelo, on Isla de Cabras, Puerto Rico San Juan del Bayou, a previous name of Spanish Fort, New Orleans