Castelsardo is situated on the coast of northern Sardinia, north-east of Sassari.
A sizeable small town with a myriad of small streets to explore, Castelsardo is a pretty place of pastel-coloured houses, with the clear blue waters of the Golfo dell'Asinara to the north and a ruined medieval (12th century) castle on a rock standing above the the town - there is a popular Museum within the castle.
Other sights within the town include the Cathedral of Saint Anthony Abbot with its well-known altarpiece of the Mother and Child (possibly by Cavaro), and the crypt below the cathedral; a sprinkling of small churches and palaces (eg the Palazzo La Loggia that houses the current town hall); the harbour region.
There are also said to be more than 50 restaurants in the town, many serving the quality local seafood, so Castelsardo is a great place to stop for a meal.
A curious site near to castelsardo is the 'elephant rock' - a large rock in a pretty spot on the road towards nearby San Giovanni that bears a remarkable resemblance to an elephant, that contains a so-called Domus de Janus (an ancient burial cave).
Note: Castelsardo is one of two villages on Sardinia classified as 'most beautiful villages in Italy' (the other is Bosa).