Montebello Castle is located to the east of the town center. It was built before 1313 for the pro-Imperial Rusca family, who occupied the castle following the Visconti victory and occupation of Castelgrande. Unlike Castelgrande, Montebello was not protected by natural features. It is surrounded by deep moats that protected the walls. The complex is rhomboid in shape and connected to the city walls on the south and north.
The inner keep dates from before 1313 and is an irregular rectangle. It appears that the battlemented tower with a hip roof on the north-east side of the keep is an incorrect reconstruction from 1903. Prints from the 17th century show a four-story building with a roof sloped toward the interior of the keep.The keep was built with a high, strong outer wall with living quarters and utility buildings along the inner wall.