The Adige is a river with its source in the Alpine province of Bolzano near the Italian border with Austria and Switzerland. At in length, it is the second longest river in Italy, after the Po river at . The river sources near the Reschen Pass close to the borders with Austria and Switzerland above the Inn valley. It flows through the artificial alpine Lake Reschen. The lake is known for the church tower that marks the site of the former village of Alt Graun ("Old Graun"); it was evacuated and flooded in 1953 after the dam was finished. Near Glurns, the Rom river joins from the Swiss Val Müstair.
The Adige runs eastbound through the Vinschgau to Merano, where it is met by the Passer river from the north. The section between Merano and Bolzano is called the Etschtal, meaning Adige Valley. South of Bolzano, the river is joined by the Eisack and turns south through a valley which has always been one of the major migration routes through the Alps, connecting the Reschen and the Brenner passes considered the easiest of the main Alpine passes. The Chiusa di Salorno narrows at Salorno mark the southernmost part of the predominantly German-speaking province of Bolzano (Alto Adige).
The Adige was mentioned in the " Lied der Deutschen" of 1841 as the southern border of the German language area (which it still is). In 1922 Germany adopted the song as its national anthem, although by that time Italy had taken control of all of the Adige. Near Trento, the Avisio, Noce, and Fersina rivers join. The Adige crosses Trento Province and later Veneto Region, flowing past the city of Rovereto, Verona and the town Adria through the Lagarina Valley and the north-eastern part of the Po Plain into the Adriatic Sea. The Adige and the Po run parallel in the river delta without properly joining. The Adige is connected through artificial underground canals to Lake Garda for flood prevention, the Mori-Torbole tunnel.