Oristano (; ) is the capital and largest city of the Province of Oristano in the central-western part of the autonomous island region of Sardinia in Italy. It is located on the northern part of the Campidano plain. It was established as the provincial capital on 16 July 1974. As of 2025, with a population of 30,007, Oristano is the 7th-largest city in Sardinia. and founded close to the ancient Phoenician settlement of Othoca (now Santa Giusta). It acquired importance in 1070, when, as a result of the frequent Saracen attacks, Archbishop Torcotorio made it the seat of the bishopric, which was previously in the nearby coastal town of Tharros. It also became the capital of the "Judicate" (equivalent to a Kingdom) of Arborea. Consequently, fortifications were designed, but the building thereof went on until judge Mariano II rose to power.
thumb|Medieval walls
In medieval times Oristano vied for power over the whole island of Sardinia, and therefore waged wars against the other Sardinian kingdoms which culminated in the attempt to conquer the whole island during the reign (1347–75) of Mariano IV and that of his son Hugh III (1376–1383) and his daughter Eleanor (1383–1404). The Judicate of Arborea held out to be the last Sardinian kingdom to cease to exist in 1420, about 10 years after the battle of Sanluri. It was transformed in Marchesato by the Aragonese and conquered, following a revolt by the last marquess Leonardo Alagon, by the Catalan troops of the Kingdom of Sardinia, in 1478 after the battle of Macomer.
Thereafter, Oristano's history was that of the island of Sardinia, characterised by the Aragonese-Spanish (until 1708) and Piedmontese (from 1720) dominations, and then the unification of Italy.
In April 1921, David Cova, Emilio Lussu, Camillo Bellieni and other Sardinian veterans of World War I founded in the city the Sardinian Action Party.
Climate
center|thumb|View of the city
Oristano has a subtropical mediterranean climate with hot summers and mild winters. As manifests a mediterranean climate, precipitation patterns are highly seasonally defined, with the vast majority falling during winter. Summers are still retaining warmth and humidity during night in spite of the dry weather.
Demographics
As of 2025, Oristano has a population of 30,007, of whom 47.3% are male and 52.7% are female. Minors make up 10.8% of the population, and seniors make up 29.8%, compared to the Italian average of 14.9% and 24.7% respectively.
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|+Foreign population by country of birth (2024)