Castelpetroso is a municipality in the Province of Isernia in the Italian region Molise, located about 25 km west of Campobasso and about 10 km south-east of Isernia.
Maria Santissima Addolorata is the nickname with which Catholics venerate Maria following the apparitions that, in 1888, two peasant women at Castelpetroso, in the province of Isernia . Following this episode Carlo Acquaderni promoted, together with bishop Palmieri, a fundraiser for the construction of a sanctuary, which was designed by the engineer Francesco Gualandi of Bologna. The first stone was laid on September 28, 1890, while the consecration and inauguration took place on September 21, 1975.