Immediately neighbouring [St. Helena](/ava/st-helena-ava) and [Diamond Mountain District](/ava/diamond-mountain-district-ava) in the northwest of [Napa Valley](/ava/napa-valley-ava), Spring Mountain District AVA covers a geographic region of around three and a half thousand hectares, of which approximately 12% is planted to vine. This is an area of snaking roads and dense forest; a region of rugged natural beauty and an air of mystery. The vineyards - occupying steep slopes and terraces - are almost universally small and the wineries, of which there are currently around thirty, are bespoke, family-run operations whose proprietors are invariably driven by a passion for the land and a commitment to expressing its nuances through their wines. Often described as the coolest and wettest of the [Napa Valley](/ava/napa-valley-ava) sub-appellations, Spring Mountain’s climate is characterised by warmer nights and cooler days compared with the valley floor. The elevation diversity - ranging from two-hundred to eight-hundred metres above sea level - and the various aspects of the vineyards also has an effect on the microclimate for specific plots. With almost 90% of Spring Mountain District’s wine coming from red varieties, it is no surprise that [Californian](/region/california) favourite [Cabernet Sauvignon](/cabernet-sauvignon) is the key grape cultivated in this appellation. It delivers powerful, rich wines with intense blackcurrant flavours and the potential to age very well. [Merlot](/merlot), [Cabernet Franc](/cabernet-franc) and [Zinfandel](/zinfandel) are also prevalent in Spring Mountain vineyards and [Chardonnay](/chardonnay) is the principal white grape.