The origins of the town's name derive from the original medieval Sardinian name "San Teoru" (San Teodoro, had been transformed into Sancte Eru). The settlers, originally from the Piedmont, translated and amended the name into San Vero, to which the name "Milis" was later added to avoid confusion with the similarities of a eponymous municipality of the Campidano of Simaxis area. Town in the province of Oristano, located in Campidano, in the central-western part of Sardinia, at the foot of the mountain chain of Montiferru and extends up until the Sinis Peninsula, not far from the sea. The territory is characterized by an extremely heterogeneous environment, rich in lakes (Sale 'e Porcus and Is Benas) and fauna with several species of birds. The town is famous for the production of wooden baskets and fine wines.
Thanks to the abundance of water, the area was inhabited since the Neolithic times. There are several traces of villages, burial grounds and nuraghi. The rich soil of the surrounding territories were intensively cultivated during the periods of Phoenician, Carthaginian and Roman dominations. After the fall of the Roman Empire, the local economy was diversified and, in addition to the cultivation of wheat and the harvest of salt, the local inhabitants started the production of wine, the cultivation of olives and the breeding of livestock and fish. During the Middle Ages, San Viro was part of the Parish of Milis and included into the Giudicato of Arborea. Under the Aragon domination, it submitted frequent pirate attacks, until these built several watchtowers to protect the whole area.
- the Parish Church of St. Sophia, located in the town center. It was rebuilt in the XVII century on the remains of an earlier Romanesque style building, of which traces are still visible in the walls and in the apse. The eclectic façade is characterized by the presence of three sculptured portals and a central rosette window. Within a wide single nave with a barrel vault and six chapels. Inside the chancel there is an altar decorated with colored marble. The church is flanked by a beautiful and massive square Bell Tower, in Baroque style, surmounted by a dome;
- the church of San Michele Arcangelo, which was built between the late XVI and early XVII centuries. It was later enlarged with the addition of two aisles;
- the prehistoric traces and the Nuraghe, including the one of s'Uraki;
- the Lakes of Is Benas and Sale Porcus;
- the Watchtowers.