Its name seems to be of Celtic origin.
It rises on the northern slope of the Maladeta massif, at an altitude of 2,500 metres. Well-known municipalities of the province of Huesca such as Benasque and Campo are located in its valley. It is a typical Pyrenean river, fed by the melting of the Aneto glacier and the high rainfall at its headwaters, where its waters are dammed for hydroelectric use in the Paso Nuevo reservoir-between Benasque and Plan del Hospital and the Linsoles reservoir along to Eriste.
In summer its banks become a popular place for water activities.