The Ache rises on the Reinkarsee at about m (AA), at the foot of the Kröndlhorn, and its middle reaches run through a roughly long gorge. In Hopfgarten the Windauer Ache discharges into the Brixentaler Ache at a narrow point in the valley; the Brixentaler Ache in turn empties into the River Inn at Wörgl.