Coropuna is the largest and highest volcano in Peru, attaining an elevation of 6,425 metres (21,079 ft). It is located about 150 km (90 mi) northwest of Arequipa, the second largest city in Peru. This massive ice-covered stratovolcano complex has a summit plateau which extends over 12 x 20 km (8 x 13 mi), with six separate summit cones rising above it. Three summits have over 300 m of prominence, the true summit, 6,425m, is at the northwest corner of the plateau.
The southwest summit Kasulla (Casulla) has an elevation of 6,377m on the Peruvian IGM map but may be equal or greater in height depending on the depth of seasonal snow. A further summit with over 300 m prominence is Coropuna E, 6,307 m high. A permanent ice cap of about 130 square kilometres (50 sq mi) in area covers the summit region, extending down to roughly 5,300 metres (17,400 ft) on the north side and 4,800 metres (15,700 ft) on the south. Vertical relief on the south flank exceeds 4,000 metres (13,000 ft) over a distance of less than 15 km (9 mi).
The name Coropuna means "shrine on the plateau" in Quechua. Coropuna was and still is one of the most sacred mountains in Peru, and in 1553 its temple was claimed to be the fifth most important shrine in the Inca Empire by the chronicler, Cieza de Leon. In 1982 the Peruvian archaeologist José Antonio Chávez was able to briefly visit an Inca site called Achaymarka (Achaymarca), which he felt was a likely candidate to be the temple of Coropuna. In 1989 Chávez and Johan Reinhard led an expedition to visit Achaymarka and surveyed the central ruins at 4,030 m (13,222 ft), which was part of a complex of over 200 structures, including an ushnu, an Inca ceremonial platform.
They also traced an Inca Trail up to 5,500 m (18,044 ft) on the western slope of the mountain, where it disappeared beneath the glacier ice. Along this trail was an Inca site at 5,090 m (16,699 ft) that they named Aqukancha (Ajocancha). In 1996 they organized another expedition which found wool and llama bones at 5,760 m (18,897 ft), llama bones and shards at 5,947 m (19,511 ft), and wood at 6,200 m (20,341 ft), providing evidence of pre-Columbian ascents.