The church of Baltarga was consecrated by Bishop Ingobert in 891, but the current building is from the 11th century with important modifications from the 18th. Of the Romanesque apse, only the northernmost exterior remains with fine blind arches typical of the Lombard style; inside it is quadrangular, a modification designed to fit a baroque altarpiece. The rest of the apse was replaced by the sacristy. Next to the door an added body was built that functions as a support for the building and internally as two chapels. Possibly the building suffered a major collapse of the southernmost part and a subsequent reconstruction in 1771, as indicated by the inscription on one of the southern chapels, at which time the bell tower was also to be built.

The most notable of the apse fragments is the door, also in the Lombard style, with a semicircular arch with voussoirs followed by an arch of thin stones and a concentric arch with gear teeth.

The Museum of Art of Catalonia preserves an altar front from the end of the 12th or beginning of the 13th century. A high quality work depicting a central pantocrator surrounded by the symbols of the evangelists with two pairs of disciples on either side. On the other hand, in the Diocesan Museum of La Seu d’Urgell, some of the mural paintings in the apse and the arch of the presbytery from the second half of the 12th century are preserved.