Laid out in cascade along the Campo do Couto, in an extremely beautiful landscape, the O Folón and O Picón mills constitute an ensemble of great cultural and ethnographic interest. Taking advantage of the energy provided by the waters that flowed down from the mountain, these constructions were used to grind corn and wheat, as well as working with linen and wool. Their structure is divided into two parts: the "termiñado" or top floor, and the "sarteio", the area where the energy to move the mill was produced. Some of them include an adjacent watering trough for animals.

As shown on it, the oldest inscription dates back to 1702, although there seems to be documentary evidence that these facilities were in operation in the 17th century. The existence of these mills in this location is probably linked to the influence of the monks at the Santa María de Oia Monastery. Some of the mills belonged to the villages, as communal property; others were privately owned or shared among several families, and there were also some that were rented out.

In the mills' surroundings there are several trekking routes, duly signposted, which will take us to other points of interest. We will visit, for example, the nearby San Martiño Shrine or the cascade formed during the rainy season in the River das Penas. In the rocks that form the trails one can clearly see the "rodeiras", marks left by the carriage wheels (rodas) over the centuries.

In 1991 work began to recover and restore the mills and their surroundings, which were in a state of abandon at that time. The first steps were taken by the students from the Apprenticeship Training Centre. Later, in 1996, the O Rosal Town Hall, through its Workshop School, gave the project another boost. Since 1988, the O Folón and O Picón Mills Ensemble has been declared a Site of Cultural Interest (BIC, acronym in Galician).