A former truce of Ploërdut, Locuon was erected in parish in 1853, while remaining dependent on the commune. The name "Locuon" comes from the numerous LOC families, meaning "consecrated places" and the statue of Saint-Yon, sheltered in the choir of the church. This village, built on a granite site, has the distinction of being the only place in Armorica where traces of the work of the Gallo-Roman quarries are still visible. Below the church, the large rock face is the former front of a Gallo-Roman quarry. The site is recognized major since 1980. Its importance has brought about the arrival of researchers who have determined, thanks to the traces on the rock, the mode of extraction employed by the workers there is a little less than 2000 years. During archaeological excavations in Carhaix (former city of Vorgium) in 1996, cut blocks are uncovered whose granite is identical to that of Locuon. Experts attest that they come from the Ploërdut deposit. This granite is very white, without black mica, and it is probably in this that it was very popular with the Roman builders, probably reminding them of the light marbles of their native land. The chapel is a foundation of Lescobic, lords of Kerfandol. It was probably rebuilt in the 17th century with re-erections of a 16th-century building. It is called Notre-Dame de la Fosse (Chapel Vons, in Breton). You can see a link with the magnificent fountain below. The chapel is accessed by a majestic granite staircase, of which a headless statue adorns the bottom of the creeping. It would be an ancient goddess. The site of Locuon is today a place invested by artists inspired by this enigmatic place within the framework in particular of "Moving Places". Located in the heart of majestic nature, Locuon is also the starting point of a magnificent hiking loop.