The castle that once dominated Giusvalla dates back to at least the tenth century, when a fortified residence already stood above the valley of the Giusvalletta. By 1142 the site had passed into the hands of the Del Carretto family, one of the most powerful noble houses in Liguria, who held it as a fief and used it to control the mountain passes between the coast and the Piedmontese interior. Over the following centuries the castle changed hands several times — absorbed by the marquises of Ponzone and then Monferrato before the entire territory was folded into the Kingdom of Sardinia in 1735.
What remains today are the stone walls and foundations, weathered but still substantial enough to read the outline of the original keep. The ruins sit above the village on a low ridge, offering good views across the forested hillsides of the Ligurian Apennines. It is an easy walk up from the village centre — no formal path, but the route is obvious.