Castle of Pietra Ligure, Medieval castle in Pietra Ligure, Italy.

The Castle of Pietra Ligure stands on a limestone rock east of the old town center. Its walls rest directly on the rock, with vaulted passages and low cells known as the "Grimaldina". The castle reached its present size in the 16th century with a southwest wing, an east arch and two sentry boxes.

The site began as a Roman castrum on the limestone rock east of the old centre, later enlarged during the barbarian and Saracen incursions of the 6th to 9th centuries. A medieval castle arose there in the 12th century as a stronghold of the bishops of Albenga, often attacked by the Del Carretto of Finale. In 1385 Pope Urban VI ceded the surrounding borgo to Genoa, while the castle passed to the Arnaldo family at the end of the 14th century and was enlarged in 1550 with a south-west wing, an east arch and two sentry boxes.

The castle's lower rooms, the "Grimaldina", are named after two Grimaldi brothers from Monaco imprisoned there at the end of the 14th century. The medieval section was restored in the 1960s and turned into a meeting venue in May 1967. The village below the castle was ringed by towered walls with five gates, including the marina gate, protected by a bastion to the south.

The site sits within the historic quarter near the main plaza and is easily reached on foot. Paths around the rock can be uneven and steep in places, so sturdy footwear and time for exploration are recommended.

The name Pietra Ligure refers to the limestone rock east of the old town, on which the Roman castrum stood; the settlement was long called simply La Pietra. The castle's lower rooms, the "Grimaldina", held two Grimaldi brothers from Monaco imprisoned at the end of the 14th century.