The Naviglio Grande is a canal in Lombardy, northern Italy, connecting the Ticino river near Tornavento (23 km south of Sesto Calende) to the Porta Ticinese dock, also known as the Darsena, in Milan. It drops 34 m over 49.9 km. It varies in width from 22 m to 50 m from Tornavento to Abbiategrasso, dropping to 15 m between there and Milan. Initially carries 63 m³ per second, 116 outlets take water to irrigate 500 square kilometres leaving the canal 12 m wide and carrying 12 m³ per second as it enters the dock.

The Naviglio Grande was the most important of the Milanese “navigli”. Probably originating as a ditch dug in 1157 between Abbiategrasso and Landriano as a defense against Frederick Barbarossa, it was one of the largest medieval engineering projects, allowing development of commerce, transport and agriculture.

In 1177, construction began near Tornavento, but problems stopped work almost immediately. In 1179 however, a dam was constructed and water from the Ticino was directed towards Turbigo, Castelletto di Cuggiono, Bernate and Boffalora reaching Gaggiano in 1233. This 30 km section, the “Navigium de Gazano” took over 50 years to dig by hand using only pickaxe and shovel. Prisoners from Turbigo were put to work in 1239 to increase the carrying capacity of the canal.