Castello di Proh, Medieval castle in Briona, Italy.

Castello di Proh is a castle in Briona featuring a rectangular main structure with two round towers positioned at opposite corners. The building sits at the base of the Novara hills in Piedmont and is currently managed by the Fondazione UniversiCà.

In the early 12th century Conrad III of Swabia granted the fief to the counts of Biandrate, who built a fortress known as the "castellaccio" on the heights behind; it was destroyed in 1362 during the war between the Marquis of Montferrat and Galeazzo Visconti. Around the mid-15th century the site passed to the Tornielli, as did nearby Briona castle, and in 1495 it was occupied by Ludovico il Moro's army. It later went to the Caccia (1597) and the Cattaneo brothers of Novara (1672).

Inside the east wall of the courtyard survives a faded triptych of the Madonna and Child with saints; the Cattaneo coat of arms remains on the south-west tower. The castle's name is pronounced "prü" locally, and since 2020 the Fondazione UniversiCà has run multimedia exhibits in its rooms.

The castle has been open to the public on a stable basis since 2025, with visits to the multimedia rooms and the botanical area of the rural park, also during events. Access ways and rest areas were created for visitors, and the west side was cleared in 2021 by demolishing a dilapidated annex.

The castle's name is pronounced "prü" locally, and a 1581 map of the Duchy of Milan in the Vatican Galleries may mark the site under the toponym Pario. The entrance plaque records the 1960 restoration, which rebuilt the tallest tower beside the main gate.