Like Durro and Taüll, Erill la Vall was originally a livestock farming town. The name comes from the powerful lineage of Erill family, which built up its power in the Boí Valley in the 11th and 12th centuries. It is located at the foot of the Erill Peak (2,627 metres).
Its architecture is indebted to the traditional bordas, small rural buildings used in the past by shepherds to store tools and to shelter animals, situated at the foot of the summer pastures. Some houses in the village still have typical features like threshing floors, troughs and hay lofts.
It is looked over by the Romanesque church of Santa Eulàlia d'Erill la Vall, and is home to the Vall de Boí Centre for Romanesque Interpretation, in Batalló Street, which organizes exhibitions and courses related to the Romanesque heritage.