Insubria is a historical-geographical region which corresponds to the area inhabited in
Classical antiquity by the
Insubres; the name can also refer to the
Duchy of Milan (1395–1810). For several centuries this name stood for an area stretching approximately between the
Adda river in the east and the
Sesia river in the west, and between the
San Gottardo Pass in the north and the
Po river in the south, thus it was a synonym of the Milan region and the countryside areas gravitating towards it.