Ayacucho is a department of San Luis Province, Argentina.
With an area of it borders to the east with the departments of JunÃÂn and San MartÃÂn, to the south with Coronel Pringles and Belgrano, to the west with the provinces of Mendoza and San Juan, and to the north with San Juan, La Rioja and Córdoba, which makes it the only department in Argentina which borders four provinces.