The Po (Latin: Padus, Po, Ligurian: Bo, Greek: Eridanus) is a river that flows 652 km(405 miles) (682 km by considering the length of the system from the source of Maira River,a right side tributary) eastward across northern Italy, from Monviso (in the Cottian Alps) to the Adriatic Sea near Venice. It has a drainage area of 71,000 km² and is the longest river in Italy.
It goes through many important Italian towns, including Turin (Torino) and (indirectly) Milan (Milano), in Lombardy. It is connected to Milan through a net of channels called navigli, which Leonardo da Vinci helped design. Near the end of its course, it creates a wide delta (with hundreds of small channels and five main ones, called Po di Maestra, Po della Pila, Po delle Tolle, Po di Gnocca and Po di Goro) at the southern part of which is Comacchio, an area famous for eels. The Po valley corresponds to the Roman Cisalpine Gaul, divided in Cispadane Gaul (South of the Po) and Transpadane Gaul (North of the Po).
The vast valley around the Po is called the Padan plain (it: Pianura Padana) and is so efficiently connected by the river that the whole valley became the main industrial area of the country. This river is subject to the authority of a special authority, the Magistrato delle Acque.
In 2005, water from the Po was found to contain "staggering" amounts of benzoylecgonine, which is excreted by cocaine users in urine. Based on these figures, cocaine consumption was estimated to be about 4 kg daily, or 27 doses per day per thousand young adults in areas that feed into the river--a number nearly three times higher than previous estimates.