The patroness of Casarza Ligure is Saint Monica, celebrated on the second Sunday of May. The earliest official documents relating to the municipal territory record the primary place name of Candiasco: according to local history, the town must have stood in Roman times on a hill, unlike its current position in the valley floor of the Petronio stream.
The town preserves several historic churches, including the 17th-century parish church of San Michele Arcangelo, that of San Martino in the hamlet of Bargone, and the church of San Giovanni Battista in the locality of Candiasco, first mentioned in a document from 1100. Casarza Ligure is also home to the «Parma Gemma» mineralogy museum, which holds specimens from the Ligurian and Tuscan-Emilian Apennines, including silver recovered within the municipal territory itself.
