Its source is in the Circo de Pineta, in the Ordesa y Monte Perdido National Park, in the Aragonese Pyrenees.

The Cinca is born in the area of Pineta and begins its descent between cascades and torrents, in the mountains of the Tres Sorores.

Upon reaching Aínsa, it is joined on the right side by the Ara River, where the Mediano Reservoir is located.

Just after this, it is joined on the left side by the Ésera River, the Cinca's most important tributary.

The migratory villages, in the first Iron Age, used the Cinca Valley in their path to the interior; they were populated by the Ilergetes.