The patroness of Castelbianco is Our Lady of the Assumption, celebrated on 15 August. The parish church dedicated to her, in the main hamlet of Veravo, was built in Baroque style and holds a fine 18th-century organ.
The name Castelbianco derives from a small, ancient defensive outpost, whose ruins survive just above Veravo, visually connected to the castle of Alto in Piedmont and also used as a toll-collection point along the route between the Ligurian coast and the Piedmontese side. A little further up, at the Garscin locality, stand the remains of the ancient castle built by the marquises of Clavesana to consolidate their domains in the Pennavaira and Neva valleys: passed to the Del Carretto family and their vassals the Cepollini of Albenga in the 14th century, it was finally used by the Republic of Genoa as a small garrison.
