The Ourthe River begins when two tributaries come together: the Western Ourthe which rises near the town of Ourthe, and the Eastern Ourthe which rises near the town of Ourt. All of this takes place in the Province of Luxembourg.
The Ourthe itself is divided by the town of La-Roche-en-Ardenne into Upper and Lower. The Upper Ourthe is a narrow, swift, bubbling torrent, while the Lower Ourthe is more placid. The Lower Ourthe flows into the Meuse River at Liege.