Lardirago Castle, Medieval castle in Lardirago, Italy.

Lardirago Castle is a medieval fortress featuring a rectangular layout organized around a central courtyard. The structure is defined by a columned portico with pointed arches and a substantial defensive tower positioned at one corner.

Lardirago is documented from 1254, when the monastery of San Pietro in Ciel d'Oro invested Bonifacio Beccaria with woods before the castle gate; masonry in the chapel of San Gervasio dates to the 11th–12th centuries. In the second half of the 14th century the Visconti occupied it and Gian Galeazzo promoted building works; the monks regained it around 1410. In 1447 it hosted Francesco Sforza, and in 1512 it was sacked by Swiss and Venetian troops. Pope Pius V assigned it to the Collegio Ghislieri in 1569.

The name Lardirago appears in written records from 1254, when the monastery of San Pietro in Ciel d'Oro invested Bonifacio Beccaria with woods at Spirago before the castle gate. Since about 2000 the Collegio Ghislieri has restored the complex for conferences, seminars, advanced courses and concerts, which now occupy its renovated halls and classrooms.

Since around 2000 the Collegio Ghislieri has restored the whole complex for cultural, congress and exhibition use; renovated halls now host conferences, seminars, advanced training courses and concerts. The castle stands in Lardirago, near the Olona and almost on the old border between the Pavia and Milan districts. Access follows the programme of these events, so check what is scheduled before travelling.

The large 13th-century entrance portal alternates trapezoidal blocks of pale sandstone with pairs of brick blocks in its arch, a Lombard technique of the period. It originally held a metal portcullis. The south ricetto enclosure, added in the second half of the 14th century, housed a mill, a press, a pounding mill and a water-powered saw.