Nostra Signora di Castro, Romanesque church in Oschiri, Italy.

Nostra Signora di Castro is a Romanesque church built of red trachyte blocks in the countryside of Oschiri. Its gabled facade, framed by corner pilasters, is divided into three sections by lesenes and topped by a two-bell gable bell tower. The interior has a single rectangular nave 11.60 m long and 5.60 m wide, with a semicircular east-facing apse and a wooden truss roof.

The diocese of Castro is documented from 1116, when an anonymous episcopus castrensis attended the consecration of the basilica of Saccargia. According to the Liber Judicum Turritanorum, the cathedral was founded by Judge Mariano I of Torres between 1065 and 1082. It was consecrated by the same papal legate who consecrated Sant'Antioco di Bisarcio on 1 September 1164 or 1174, and was completed by 1174. The diocese was suppressed in 1503 and later became a titular see.

The church is the goal of an annual pilgrimage for the inhabitants of Oschiri, who reach it on foot through the countryside. The rural sanctuary is enclosed by cumbessias, rustic lodgings for pilgrims typical of Sardinian campestre shrines, built after the Romanesque church. The building also appears in the official coat of arms of the municipality.

The church stands in open countryside in the territory of Oschiri, on the site of the old episcopal citadel of Castro, and the enclosure is formed by the cumbessias, the rustic pilgrim lodgings, with a porch against the left flank. Access is from the surrounding country roads, so plan for a rural walk rather than a town visit.

The church appears in the official coat of arms of Oschiri, and the annual pilgrimage of the town's inhabitants ends here. The trachytic blocks give the building its red colour, and the interior preserves a wooden retablo from the late 17th or early 18th century.