Castello di Santa Maria Coghinas, Medieval castle in Santa Maria Coghinas, Italy.

Castello di Santa Maria Coghinas, also known as Casteldoria, is a ruined medieval fortress on a granite hill about 220 metres above sea level. Its best-preserved structure is the pentagonal Doria tower, over 20 metres high, with a north-east door, two large openings and a first-floor window; inside are three wooden levels and a tiled roof walkway. Some wall sections, a chapel ruin and a large cistern remain.

The castle was built during the Middle Ages to control the surrounding territory and key routes in northern Sardinia. Over time it changed hands several times and gradually fell into ruin, leaving the stone remains that can be seen today.

The name Casteldoria ties the castle to the Doria family of Genoa, who built it around the 12th century. By 1321 the walls enclosed houses, vegetable plots and cultivated fields, and a document records the castellan Pietro de Barra granting the locality of Gorgoiosa to the burghers for cultivation inside the walls. About 13 heads of household, some 40 to 60 people, lived in the borgo in 1361.

The site is reached from Santa Maria Coghinas by local roads, but the final stretch involves walking on uneven ground. Sturdy shoes are a good idea, and leaving enough time to move between the different parts of the ruins makes the visit easier.

The keep that still marks the hill is a five-sided tower over 20 metres high, with a doorway on the north-east side and two unaligned openings above it. Inside, three wooden floors once rose to a tiled roof walkway, and traces of the original beams survive.