The Colorado River marks most of the political boundary between the Argentine provinces of Neuquén and Mendoza, and between Rio Negro and La Pampa.

Its man-made dam, "Embalse Casa de Piedra," serves both to generate hydroelectricity for the arid region the river traverses, and to regulate the river's water level.

Its sources are on the eastern slopes of the Andes in the same latitude as the Chilean volcano Tinguiririca (about 34° 48' S.) and the river takes a generally east-southeast course toward the Atlantic Ocean.

After leaving the vicinity of the Andes, the Colorado flows through a barren, arid territory, and receives no tributary of note except the Salado (or Curacó) from La Pampa Province—although it was once an outlet of the now-closed lake basin of Laguna Urre Lauquen.

[3] The river ends about 100 to 120 kilometres (62 to 75 mi) south of Bahía Blanca, through several channels of a delta of the Unión Bay extending from latitude 39° 30' to 39° 50' S. Its total length is about 1,000 kilometres (620 mi), of which about 300 kilometres (190 mi), from the coast up to Pichi Mahuida, are navigable for vessels of up to 2 metres (7 ft) draft.