Which river is the longest in Italy?

The Po is the longest river in Italy.

The Po begins at Pian del Re beneath Monviso in the Cottian Alps of Piedmont. It then flows generally eastward across northern Italy, passing near or through major cities including Turin, Piacenza, Cremona and Ferrara before entering the Adriatic Sea through a broad delta.

The river gives its name to the Po Valley, or Pianura Padana, one of Italy's most productive agricultural and industrial regions. Its water supports rice cultivation, vineyards, manufacturing and large urban populations. In antiquity, the surrounding plain was known to the Romans as Cisalpine Gaul.

The main alternatives can be misleading: the Adige is Italy's second-longest river, while the Tiber is the river associated with Rome and the Arno with Florence. Another nuance is that the Drava originates in Italy, but most of its course lies outside the country; the Po is the longest river flowing substantially across Italy and is conventionally recognized as the nation's longest.