Municipality in the province of Sassari, situated on a promontory jutting into the sea, at the centre of the Gulf dell'Asinara, in the Northern corner of the island of Sardinia, the village of Castelsardo, with its narrow streets, is dominated by the imposing bulk of its medieval castle. Its particular location offers a splendid view over the surrounding coast and in the distance, a stretch of coast of the nearby island of Corsica.
The structure of the territory and the presence of natural shelters were the basic elements that induced the first settlers to built their hamlets here, since the pre-nuragic period. This area was colonized by the Romans, who established here a trading post. After the fall of the Empire, most of the lands were donated to the various monastic orders. Between the XII and XIII centuries, the town was assigned to the Doria (a family of Genoese origins), who founded the castle and named it Castelgenovese. The local inhabitants slowly moved and sheltered within the fortifications that were equipped with strong tall walls. Castelsardo belonged to the Doria until 1448, when it was incoporated into the Giudicato of Arborea. Later conquered by the Aragonese, in the XVIII century, the town was under the control of the Savoy, who entitled the centre with its present name.

Attractions:
- the Cathedral of St. Anthony Abbot, which dates back to the Aragonese period. It features a very simple façade, preceded by a square that overlooks the sea and is flanked by a Bell Tower with a square base and an octagonal form towards the top and a dome covered with tiles. It features a single nave plan, originally built in Romanesque style, today proposes several late Gothic decorative elements. Inside are preserved, pieces of wooden furniture that date back to the XVII and XVIII centuries and a late XV century altarpiece;
- the Church of Santa Maria delle Grazie, originally built in Romanesque style, has been refurbished inside in Baroque style;
- the XII century Loggia, today houses the seat of the City Council;
- the pre-nuragic walls of Monte Ossona;
- the rock entitled to the elephant;
- the Castle of the Doria;
- the Palace of the Doria;
- the Nuraghe Paddaju.