The province of Oristano (Italian: provincia di Oristano, Sardinian: provìntzia de Aristanis) is a province in the autonomous island region of Sardinia in Italy. Its capital is the city of Oristano. It has an area of 3,040 square kilometres (1,170 sq mi), a total population of 167,971 (2001), and a population density of 55.2 people per square kilometer. There are 78 municipalities (comuni) in the province).
The town Arborea was founded by Benito Mussolini's fascist regime as Mussolinia to be an experimental town, for which, farmers were moved from Emilia Romagna and Veneto. The River Tirso flows through the province of Oristano from the province of Nuoro, and its mouth is located at the Gulf of Oristano. Temo is the only other river to flow through the province. The town of Bosa is located in the region alongside a river and its medieval fortifications remain. The province of Oristano was formed in 1975 and had been largely unaffected/undamaged by tourism.