Po

Po (ancient Padus), river, northern Italy, the longest in the country. Rising in the north-west near the border with France, on Monte Viso in the Cottian Alps, it flows east for a distance of about 670 km (417 mi), past the cities of Turin, Chivasso, Trino, Piacenza, Cremona, Casalmaggiore, Viadana, Ferrara, and Porto Tolle, into the Adriatic Sea. Its drainage basin covers a large portion of the region, and the wide plain through which it flows is Italy's main agricultural centre. Its tributaries are the Tanaro, Dora Baltea, Dora Riparia, Ticino, Adda, Oglio, Mincio, Trebbia, Taro, Panaro, and Secchia rivers. The surface of the river along its lower course is high, and the land is protected by canals, levees, and dykes. The river is navigable for some 555 km (345 mi), from the Adriatic Sea to Casale Monferrato, a city in Piedmont; it is also used for irrigation. Deposits of silt, brought by many tributaries, are enlarging the delta of the Po at the mouth of the river to the extent that the delta is advancing into the Adriatic Sea at the rate of about 60 m (200 ft) per year. The Po delta cultural landscape was inscribed on the UNESCO World Heritage list in 1999.