The Horse Heaven Hills AVA was established in 2005 and is home of some of the state's largest and oldest vineyards. Of the region's , nearly were planted as of 2008. The boundaries of the AVA follow its namesake hills to the north which forms the southern border of the Yakima Valley and extends southward to the Columbia River. In 1972, the first vineyard planted in this region was called Mercer Ranch. Now known as Champoux Vineyard, it is one of the most prestigious and sought after grapes in the state with its name appearing on several vineyard designated wines. The vineyard is also home to some of the oldest Cabernet Sauvignon vines in the country. Many of the best vineyards are planted along the right bank of the Columbia River, though some areas are prone to exposure to winds in excess of at which point vines are at risk of shutting down metabolically, thereby hindering the ripening process. However the wind also serves to toughen grape skins, which can moderate temperatures, increase phenols, and keep the vine's canopy dry which aids in disease control.