A single-vessel building built of granite and schist rubble, the Saint-Petrock de Trégon church, in Beaussais-sur-Mer, in the Côtes-d'Armor, has been partly rebuilt over the centuries. The building reveals angular buttresses with projections, as well as a bell tower in-work of square plan.
Mentioned from the second half of the 12th century, the church of Trégon has a 12th century portal with a quadrilobe frieze from the 15th century. The current building dates from the 19th century.