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. The bottom lands of the Colorado, in its course across
Patagonia, are fertile and wooded, but too small in area to support more than a small, scattered population. The river ends about 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 , of which about , from the coast up to
Pichi Mahuida, are navigable for vessels of up to
draft. It is nearly if calculated
Río Desaguadero within. ==Naming==