Since the erection of the Vogogna Rocca, probably a rampart defended the path that led to it from the site of the current castle. Here, a rectangular tower controlled the way's access. In the 14th century, the Visconti of Milan built the present castle. A long body, parallel to the way to the Rocca, was added to the west of the rectangular tower. At the end of the new body, toward the town, an imposing semicircular tower was erected. Along the southern side, a fortified wedge-shaped parade ground was added.
Castle ground plan, entrance door, and other architectural details.
In 1446, Filippo Maria Visconti granted the castle and its territory to his treasurer Vitaliano Borromeo, a banker of Tuscan descent. In 1487, the Sforza confirmed it to the Borromeo family. For about three centuries, it remained almost continuously among their possessions.[5] In 1515, Swiss troops, supported by men from the upper Val d'Ossola, occupied and damaged the castle.
In 1797, the castle passed into French hands during the Napoleonic era and then became municipal property. The tower was used as a prison, while the rest of the building as a dwelling and warehouse. In the 20th century, the Vogogna municipality gave increasing attention to the historical importance of the castle. The first restorations date back to 1927. They were completed in 2001.
(source, wiki)