Colorado is a state in the American west, bordered by New Mexico to the south and Wyoming to the north. Colorado's vineyards are among the highest in the world, reaching altitudes of 7000ft (2135m) in the Rocky Mountains and rivaling even the famously lofty Andean vineyards of Argentina. Viticulture at this height produces wine with vibrant, intense colors and aromas, created by the intensity of the sunlight and cool nights. The better Colorado wines are made from such grape varieties as Merlot, Cabernet Sauvignon, Riesling and Chardonnay.
The state covers just under 105,000 square miles (270,000 sq km) of land between latitudes 37°N and 41°N, ranging from the Rockies to the lower-lying ground in the east. The climate in Colorado is typically continental; the nearest large bodies of water are well over 500 miles (800km) away. This results in warm, dry summers, as well as in cold winters (particularly in the higher areas) that pose significant risks to less-hardy vines.
Most of Colorado's wine industry can be found along the state's western border with Utah, in the high-altitude soils of the Rocky Mountains. Here, the altitude helps to moderate the climate, and the rocky, sandy soils have proved well suited to viticulture. Low annual rainfall in these parts of Colorado allows growers careful control over vigor and yields through the sparing use of irrigation.
Winemaking in Colorado dates back well over 100 years; wine production was first recorded here in the 1880s, and by 1909, the state was harvesting grapes from more than 1000 vineyards. This burgeoning industry was interrupted when Prohibition was adopted in Colorado in 1916 – four years earlier than in many other US states. Many of the vineyards were replanted to peaches, now one of the state's most important crops.
It was half a century before Colorado's wine industry began to recover, in the mid-1970s when government-aided viticultural research was carried out by Colorado State University. Now there are around 100 wineries across the state, and their vineyards are planted with a combination of well-known vinifera varieties as well as purpose-made hybrids designed to endure the harsh winters here. The majority of the vineyards are in the Grand Valley, the first of Colorado's two AVAs, inaugurated in 1991. The state's West Elks AVA is home to the northern hemisphere's highest commercial winery, Terror Creek, located at 6400ft (1950m) above sea level.