The Colorado River (Spanish: Río Colorado) is a river in the south of Argentina. It has its sources on the eastern slopes of the Andes in the latitude of the Chilean volcano Tinguiririca (about 34° 48' S.), and pursues a general east-southeast course to the Atlantic Ocean, where it discharges through several channels of a delta extending from latitude 39° 30' to 39° 50' S. Its total length is about 620 miles, of which about 200 miles from the coast up to Pichemahuida is navigable for vessels of 7 ft. draft. Note that the geology in this article currently reflects views from the first decade of the 20th century. ... Nile River delta, as seen from Earth orbit. ...

This river has been usually described as being formed by the confluence of the Grande and Barrancas, but as the latter is only a small stream compared with the Grande it is better described as a tributary, and the Grande as a part of the main river under another name. After leaving the vicinity of the Andes, the Colorado flows through a barren, arid territory and receives no tributary of note except the Curaco, which has its sources in the Pampas, and is considered to be part of the ancient outlet of the now closed lacustrine basin of southern Mendoza. The bottom lands of the Colorado in its course across Patagonia are fertile and wooded, but their area is too limited to support more than a small, scattered population. Note that the geology in this article currently reflects views from the first decade of the 20th century. ... The pampas (from Quechua for plain) are the fertile lowlands that extend across c. ... Park of General San Martín in Mendoza. ... Patagonia is that portion of South America which, to the east of the Andes, lies mainly south of the Rio Negro (41°S), and, to the west of the Andes, south of (42°S). ...