Rovigo stands on the low ground known as Polesine and on the Adigetto Canal. The comune of Rovigo extends between the rivers Adige and Canal Bianco, 40 km W of the Adriatic Sea, except the frazione of Fenil del Turco that extends south of the Canal Bianco.
Polesine is the name of the low ground between the lower courses of the rivers Adige and Po and the sea; the derivation of the name is much discussed, generally applied only to the province of Rovigo, but is sometimes extended to the neighborhood of Adria and Ferrara.
Rovigo appears to be first mentioned in a document from Ravenna dating April 24, 838; the origin of the name is uncertain. In 920 it was selected as his temporary residence by the bishop of Adria, Paolo Cattaneo, on the destruction of his city by the Hungarian ravagers; the fortifications started by him were already finished in 945. The viscounts of Rovigo built a line of brick walls in the 1130s in the name of the House of Este. The current Torre Donŕ is a remnant of the castle built some time in between.
In 1194 Rovigo became a formal possession of Azzo VI d'Este, duke of Ferrara, who took the title of conte of Rovigo. The Este authority ended in 1482, when the Venetians took the place by siege and retained possession of it by the peace of 1484. Although the Este recovered the city during the War of the League of Cambrai, the Venetians, returning in 1514, retained possession till the French Revolution. In 1806 Napoleon I Bonaparte created it a duché grand-fief for general Anne Jean Marie René Savary. The Austrians in 1815 created it a royal city.
Rovigo was annexed to the Kingdom of Italy in 1861. The architecture of the Rovigo bears the stamp both of Venetian and of Ferrarese influence.