Sini is a comune (municipality) in the Province of Oristano in the Italian region Sardinia, located about 60 kilometres (37 mi) northwest of Cagliari and about 30 kilometres (19 mi) southeast of Oristano. As of juli 2021, it had a population of 400. an area of 8.7 square kilometres (3.4 sq mi) in dec 2004.[3]