It is born from glaciers on the Maipo, a volcano in the Andes range in the Argentine–Chilean border, and flows east until emptying in the Desaguadero River.
Its drainage basin covers an area of 2,750 square kilometres (1,060 sq mi) in the central region of Mendoza.
It has an average flow of 33 cubic metres per second (1,200 cu ft/s), with its maximum during the spring and summer; the October–March period accounts for 70 percent of the annual water volume.
It turns in a gentle arc, passing south of the city of San Rafael, in the geographical center of Mendoza, where it is used for irrigation (together with the Atuel River).
The river splits in multiple branches shortly before reaching the Desaguadero (here called Salado), on the border with the province of San Luis.