Montmains is both an individual Premier Cru climat site in Chablis that sits just to the southwest of Chablis town, as well as a flag-bearing, or umbrella, title that also covers the Premier Cru vineyards of Forets and Butteaux as one progresses further southwest towards the village of Courgis.

The vineyards of the umbrella Montmains vineyard occupy 118 hectares (291 acres) of southeast facing slope in a valley that runs parallel (and with similar aspect) to that of Vaillons, just over the hill to the north.

The individual Montmains section sits on the lower slopes, at the tip of the valley, as it runs into Chablis town. Here, the slope faces slightly more east, with more exposure to the cool winds of the Serein valley, albeit with good orientation for the morning sun.