Piana Crixia sits on the northern slope of the Ligurian Apennines in the valley of the Bormida di Spigno, well inland from the coast. The main reason to come here is the Fungo di Piana Crixia — a striking mushroom-shaped rock formation created by an unusual process of erosion, now protected as a natural monument.
The commune itself is a quiet cluster of stone houses surrounded by vineyards and dense natural vegetation. Perhaps of Roman origin, it was devastated by Saracens at the beginning of the tenth century and later became a possession of the Del Carretto family, who built a castle in the hamlet of Borgio. The baroque parish church, dedicated to Saints Eugenius, Victor, and Corona, dates from 1715–1765. In the hamlet of Borgio, the ruins of a medieval castle stand alongside a nineteenth-century pseudo-medieval one.