The source is located in the Switzerland Alps above the Engadin region. It runs eastwards through the Austrian state of Tyrol and passes the border to Bavaria near Kufstein.
On Bavarian territory the river runs northwards and passes the cities of Rosenheim, Wasserburg and Waldkraiburg; then it turns east, runs through M?ldorf and Neu?ting and is enlarged by two major affluents, the Alz and the Salzach.
From here to its border it forms the border between Germany (Bavaria) and Austria (Salzburg). Cities on this last section of the river are Simbach, Braunau and Sch?ding. In the city of Passau the Inn finally enters the Danube.