The majority of the region's winemaking (about 90%) takes place in the southern part of Piedmont around the towns of Alba (in Cuneo), Asti and Alessandria. The Piedmont region is located in the foothills of the Alps forming its border with France and Switzerland. In addition to the vast mountainous terrain, the Po Valley consumes a large area of available land-leaving only 30% of the region suitable for vineyard plantings. The valley and the mountains do contribute to the areas noted fog cover which aides in the ripening of the Nebbiolo grape, the predominantly grown grape in the region.