The Po (; and Eridanus; ; ancient Ligurian: Bodincus or Bodencus; and Ἠριδανός) is a river that flows either or – considering the length of the Maira, a right bank tributary – eastward across northern Italy, from a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face of Monviso (in the Cottian Alps) through a delta projecting into the Adriatic Sea near Venice. It has a drainage area of 74,000 km² in all, 70,000 in Italy, of which 41,000 is in montane environments and 29,000 on the plain. The Po is the longest river in Italy; at its widest point its width is . The Po extends along the 45th parallel north.