Castello di Riva, Medieval castle in Ponte dell'Olio, Italy.

Castello di Riva is a fortified complex on the right bank of the Nure, built largely from river pebbles and rubble stone from the stream bed. A moat fed by the Nure surrounds it on the south and east, and the ditch system with the stream on the west protected it from attack. The medieval layout was rebuilt in neo-medieval style from 1884, when the keep was raised and curtain walls with battlements added.

A feudal investiture of 1199, held under a portico ringed by walls, is the first record of a castle at Riva. The Del Cairo family rebuilt it in medieval form, completed in 1277 as an internal inscription states. In 1323 Oberto Del Cairo sold it to the Anguissola of Vigolzone for 5,600 lire, and in 1567 Duke Ottavio Farnese bought it.

The name Riva comes from the right bank of the Nure, where the castle was built to control the valley route toward Liguria and the Lunigiana. A legend tells of a Florentine noblewoman, guest of Beatrice Tedeschi, who stole the castle treasure for love, buried it near the keep and was thrown into the well; the Nure is said to glow emerald green at night like her eyes.

Parts of the site are now accessible to visitors after recent restoration work opened sections to the public. It is helpful to check in advance which areas can be visited and whether guided tours are available.

In 1412 Sigismund of Luxembourg, King of the Romans and elected emperor, stayed at the castle and there granted Bernardone Anguissola the fiefs of Riva, Grazzano and Montesanto. The Anguissola hold on Riva was later confirmed by the Visconti and then the Sforza, and a 1468 edict gave the family the title of count.