Château Grand Mayne lies to the west of St Emilion, at the foot of the plateau. As already alluded to in my introduction, near neighbors include Château Franc Mayne, which lies just a few hundred metres to the east. Others include Château Coutet, which is even closer, to the southwest, and which was once also in the possession of the Lavau family. Otherwise to the south there is Château Belle Vue and Château Angélus, to the northwest Château Laroze and Château Yon-Figeac, and to the northeast Château Franc Pourret.
Its position on the slope means that the terroir here is largely one of clay and limestone, the vines enjoying south- and west-facing positions in many cases. Some vines at the bottom of the slope are rooted in richer clay (to the south) and more sandy soils (to the west). There are 17 hectares of vines altogether, mostly planted directly around the château. The vines are dominated by Merlot at 80%, with 15% Cabernet Franc and 5% Cabernet Sauvignon, planted at a density of 5,500 vines per hectare and with an average age of 30 years. When Bernard Ginestet visited in the 1980s, the vineyard was 50% Merlot, 40% Cabernet Franc and 10% Cabernet Sauvignon, so there has clearly been a shift away from Cabernet and towards Merlot during the past two or three decades.