(ATRATUM or blackened or dark ground).
It is mentioned in 1008 as EDRADOS.
It was formerly part of the municipality of La Vega de Boñar and Abadía de Valdedios.
It is 3.2 km from Boñar, located in a mountainous area, with the Frigar Cave within its boundaries and with very interesting stalactites and stalagmites. It is also abundant in Cambrian fossils.
An iron mine exploited by the Romans has been preserved in its territory, where working tools from that period have been found. It is also famous for its pine forest. Its parish church dates back to the 17th century and its patron saint is the Asunción de la Virgen. It celebrates its patron saint’s day on 14th September in honour of Christ and the following day it celebrates the “Cristin”.