Castelsardo has a population of 5,500 people mainly occupying the village which hangs on a rocky outcrop overlooking the sea and the small seaside resort of Lu Bagnu. The historic centre of the village has all of the morphological and architectural characteristics of medieval fortified settlements.
Lying on a site, probably occupied from the end of the Nuragic period (1800 to 500 BC), the town was founded in 1102 by the Doria Family from Genoa. successively bore the names of Castel Genovese and Castel Aragonese following the Spanish conquest in 1448. It was given its present name in 1796 by the King of the Piedmont, who was also the King of Sardinia.
Since the Middle Ages, Castelsardo has been famous for its Easter Monday parade, "Lunissanti", which combines a mixture of ancient rites and traditional songs. Previously a fishing and farming village, today Castelsardo essentially lives from tourism. Castelsardo belongs to the association "Borghi pił belli d'Italia".
Castelsardo, one of the most important towns in Sardinia for its history, culture, art and tourism, has undertaken to improve its architectural heritage and its landscapes by means of a series of projects which include:
- "The itinerary of the seven royal towns of Sardinia", a tourism network associating the towns of Alghero, Bosa, Cagliari, Castelsardo, Iglesias, Oristano and Sassari.
- The network of the "Cathedrals of Sardinia", which brings together seventeen towns for the rehabilitation of this religious heritage in view of its inclusion in a programme of year-round tourism activities.