Castello di Montechiaro, Medieval castle in Rivergaro, Italy.

Castello di Montechiaro is a fortified complex on the lower hills of the Ligurian Apennines above the Trebbia valley in Rivergaro. Its irregular hexagonal first wall ring, about 15 m high and fitted with a patrol walkway, encloses a courtyard with a central keep whose shape follows the site. The keep carries Ghibelline merlons and, low down, a small stone window with a single-block arch, pointing to 13th-century work; later residential buildings lean against the wall.

Cited in the Annali Piacentini as castrum Raglii, after the nearby Rallio, the castle was probably built around the mid-12th century by the Malaspina, whose Lunigiana craftsmen left stylistic traces. Piacenza's populares destroyed it in 1234, and in 1251 Uberto Pallavicino occupied it. A notarial deed of 7 July 1324 transferred it from the Quattrocchi to the Anguissola, who held it until 1652.

The castle's name comes from the hamlet of Montechiaro, but the medieval sources call it castrum Raglii, after nearby Rallio. The Anguissola held it for centuries, and a 1374 dispute with the Fulgosio family ended with a marriage between the two houses. The Gattegno family bought it in 1990 and restored it.

The castle sits near Val Trebbia and can be reached via State Road 45 passing through the Montechiaro area of Rivergaro. Daytime visits are generally possible, and the hilltop setting offers views across the surrounding countryside.

The castle commanded the Caminus Genue, a strategic medieval route connecting Piacenza and Genoa through Trebbia Valley. This position made it a crucial waypoint for trade and travel between the coast and inland territories.