Poschiavino is an 30-kilometre (19 mi) long river that rises in the Swiss canton of Graubünden and flows into the Italian Province of Sondrio . The majority of the river is in Switzerland , with just 3 kilometres (1.9 mi) in Italy.

The source of the river lies at 2,260 metres (7,410 ft) above sea level in the Rhaetian Alps , close to the Livigno Pass . From here the river flows south through the upper Val Poschiavo , past the settlements of La Rösa , Poschiavo and Le Prese , before entering the 2.5 kilometres (1.6 mi) long Lago di Poschiavo . Below the lake, the river passes the settlements of Brusio and Campocologno before crossing the border into Italy. It flows into the Adda in Tirano , at 441 metres (1,447 ft) above sea level.