Castello Visconteo, Medieval castle near Lambro River in Monza, Italy.

The Castello Visconteo was a Visconti fortress built in 1325 beside the Lambro River near Porta Milano, on the foundations of Berengario I's castle. It had a square parade ground, a residential wing on the north side with the lord's quarters, a garden toward the river, and walls with watchtowers around a deep defensive moat. Its great tower, called dei Forni, stood about 42 meters high.

Construction began in 1325 under Galeazzo I Visconti, who wanted to secure control over the town and the road leading to Milan. In the early 1800s the fortress was pulled down completely, and its stones were reused to build the walls of the Parco di Monza.

The name Castello Visconteo comes from the Visconti family, who built it after Galeazzo I took Monza in 1325. The castle's corner tower held prisons called the forno, where prisoners were lowered through a hole into vaulted cells; Caterina Visconti died there in 1404. The site is now occupied by the former Villa Durini, built by the Durini counts in 1815 and later the Frette company headquarters.

Only foundations and archaeological traces remain on site, so there is little to see above ground. The spot is worth combining with a walk along the Lambro River or a visit to the nearby Parco di Monza, which reused the castle's own stones in its walls.

Galeazzo I Visconti personally supervised the digging of the keep's foundations, which were laid without a plan, adapting the masonry to the uneven ground and the existing roads. The keep, called the Torre dei Forni, was about 42 metres high, and prisoners were lowered through a hole into vaulted cells beneath the entrance level.