Aconcagua (Spanish pronunciation: [akoŋˈkaɣwa]) is a mountain in the Principal Cordillera of the Andes mountain range, in Mendoza Province, Argentina. It is the highest mountain in the Americas, the highest outside Asia, and the highest in both the Western Hemisphere and the Southern Hemisphere with a summit elevation of 6,961 metres (22,838 ft). It lies 112 kilometres (70 miles) northwest of the provincial capital, the city of Mendoza, about five kilometres (three miles) from San Juan Province, and 15 km (9 mi) from Argentina's border with Chile. Aconcagua is one of the Seven Summits, the highest peaks on each of the seven continents.

Aconcagua is bounded by the Valle de las Vacas to the north and east and the Valle de los Horcones Inferior to the west and south. The mountain and its surroundings are part of Aconcagua Provincial Park. The mountain has a number of glaciers. The largest glacier is the Ventisquero Horcones Inferior at about 10 km (6 mi) long, which descends from the south face to about 3,600 m (11,800 ft) in elevation near the Confluencia camp. Two other large glacier systems are the Ventisquero de las Vacas Sur and Glaciar Este/Ventisquero Relinchos system at about 5 km (3 mi) long. The best known is the northeastern or Polish Glacier, as it is a common route of ascent.