The Uco Valley (Valle de Uco) is a key winegrowing region of Mendoza, Argentina. An hour's drive south from the city of Mendoza, it is home to some of the region's most famous wines.

Argentina's primary grape variety of Malbec shines here, producing terroir-driven red wines with a distinctive floral aroma. Cabernet Franc is much less widely planted, but some great results have been achieved. In addition, some of Mendoza's finest white wines made from Chardonnay and Torrontés come from Uco Valley vineyards. The relatively cool climate allows the requisite slower ripening period.

Although considered part of the Mendoza region, the Uco Valley can be recognised in its own right on several counts. Not only is the vine-growing area quite distinct; the region is also home to several of Argentina's top producers. Attracted by the excellent climate and soil, newcomers such as the Bordeaux-based names Lurton, Dassault, Rothschild and Rolland have raised the region's profile. The vineyards of Vista Flores have produced some particularly successful wines.

Among Uco's specific merits is its high elevation at the foot of the Andes mountains. The valley's La Consulta and Tunuyan sub-regions sit at altitudes of 850 meters (2000 ft) and 1100m (3600 ft) respectively. These are slightly higher above sea level than Maipu and Luján de Cuyo in the north.

Located at a latitude of 33°S, the area's elevated vineyard sites benefit from high daytime temperatures combined with cooler nights. This allows the grapes to produce balanced sugars and acidity while achieving phenolic ripeness.

From the Tupungato region in the north to San Carlos in the south, the Uco Valley is roughly 70km (45 miles) long and 22km (15 miles) wide. The valley follows the northerly course of the Tunuyan river as it flows down from the Andean peaks. The dry continental climate brings little rain, so the river is an important resource for vineyard irrigation. The town of Tunuyan, with a population of around 45,000, is situated on the western banks of the river.

Soils throughout the Uco Valley are alluvial and fairly uniform: a clay and rock base with a stony, sandy surface. These free-draining soils are excellent for quality viticulture, as they stress the vines, leading to decreased vigour and lower yields. In turn this can lead to wines with a higher concentration of flavour.

Uco Valley has seen unprecedented investment in the past 20 years. Wine tourism is becoming one of the region's key industries. The spectacular scenery and state-of-the-art winemaking facilities has led some to portray the region as Argentina's equivalent to California's Napa Valley.