It is the highest volcano on Earth and the highest peak in Chile. The upper reaches of Ojos del Salado consist of several overlapping lava domes. lava flows and volcanic craters, with sparse ice cover. The complex extends over an area of 70–160 square kilometers (27–62 mi²) and its highest summit reaches an altitude of 6,893 meters (22,615 ft) above sea level. Numerous other volcanoes rise around Ojos del Salado.

Being close to the Arid Diagonal of South America, the mountain has extremely dry conditions, which prevent the formation of substantial glaciers and a permanent snow cover.