The Traun is a 153 km long right tributary of the Danube in Upper Austria (Austria). The mean discharge is 135 m3 / s, it drains most of the Salzkammergut. East of the Traun, the Traunviertel extends to the Enns.
The Traun rises in Styria in the Dead Mountains as Grundlseer Traun in a source, the origin of the Traun behind the Kammersee, flows through the Toplitzsee and then the Grundlsee. Between Toplitzsee and Grundlsee the course is called Toplitzoäer Toplitzbach.
In Bad Aussee the Grundlseer Traun unites with the Altausseer Traun (from the Altausseer See) and is also called Badausseer Traun, officially the United Traun ^.
Shortly afterwards, at Unterkainisch, the Kainischtraun (as Ödensee Traun from Ödensee and Riedlbach-Traun from Hochmühleck) flows into it, from here it is called Koppentraun.
This upper catchment area (excluding the Odensee) is the Ausseerland as the northern part of the Styrian Salzkammergut.
The Koppentraun flows westward through a gorge with the Koppenpass and a rail connection until it turns north on the Dachstein massif and feeds Lake Hallstatt.
It is only finally called Traun after it leaves the lake. In the middle course, initially called Goiserer Traun, it crosses the inner Salzkammergut and Bad Ischl, where it takes the Ischl from the Wolfgangsee, is called Ischler Traun and then Ebenseer Traun and maintains the northeastern direction. It flows along the Höllengebirge and at Ebensee into the Traunsee. After leaving the lake in Gmunden on the Traunstein, she is also called Gmundner Traun, leaves the Salzkammergut mountains and enters the Alpine foothills.
At Stadl-Paura it takes in the Ager from the Attersee, its largest tributary, and flows past Weis through the flat Welser Heide and touches the town of Traun. On the border between Ansfelden and Linz, a large part of the water volume at the Traun weir is diverted to the headwater canal that feeds the Linz-Kleinmünchen power plant.
The Traun flows into the Danube in the urban area of Linz, on the border between the districts of Pichling and IndustriegebietHafen (factory premises of the voestalpine).