The Aconcagua Valley is a wine-producing region of Chile, located 60 miles (100km) north of the capital, Santiago. It was long thought that this hot, dry valley was not suitable for growing wine grapes – the Chilean wine pioneer Don Maximiano Errazuriz was ridiculed when he planted his first vines here – but the quality of the region's modern-day Cabernet Sauvignon, Syrah and Merlot has robustly reversed this opinion.

The winery started by Errazuriz dominates the area but has been joined by other producers of note. 'Sena', a wine produced as a joint venture between Vina Errazuriz and Robert Mondavi, came second at the 2004 Berlin Tasting, ahead of wines from Italy and France. It is grown in a single vineyard with a unique mesoclimate at the heart of the Aconcagua Valley.

The Aconcagua Valley takes its name from the eponymous river flowing through it, which in turn is named after the 22841ft (6962m) Mt. Aconcagua at its eastern edge. This Andean giant, whose name means 'stone sentinel', is the highest mountain in the Americas and directly contributes to the terroirs found in the valley below.

Measuring around 60 miles (100km) in length, the valley runs between the slopes of the Andes in the east and the Pacific Ocean in the west. Many wine-growing areas are closely linked to the river and follow its course as it brings fresh meltwater (and mineral-laden silt) down from the Andean peaks to the valley floor. This topography, common to many of Chile's wine-growing areas, means that vineyard altitude in Aconcagua varies from 3300ft (1000m) in the east to 160ft (50m) in the west. It also creates a distinctive climatic characteristic: as the warm, dry land of the region heats up during the afternoon, the hot air in the east rises rapidly upwards, sucking in cooler air from the Pacific Ocean to the west. This process is reversed as the land cools down in the evening. These daily breezes moderate the otherwise high temperatures found in the Aconcagua Valley and reduce the risk of vine disease. The Antarctic 'Humboldt Current' which flows up the west coast of Chile helps to maintain this effect.

The Aconcagua Valley lies at a latitude of 32°S (the equivalent latitude in the northern hemisphere crosses through northern Africa and the Middle East), and it is thanks to the climatic and geographical conditions described above that quality wine can be produced in the Aconcagua Valley.