Ben Macdui, with its two neighbouring peaks Carn a' Mhaim and Derry Cairngorm, forms the central massif of the Cairngorms between the two great passes, the Lairig Ghru and the Lairig an Laoigh. Ben Macdui is a huge dome with fairly steep slopes all round except to the north where a great plateau extends to Cairn Gorm. Carn a' Mhaim is joined to Ben Macdui by a long narrow ridge which drops precipitously on its west side into the Lairig Ghru. Derry Cairngorm forms a long ridge on the west side of Glen Derry with its prominent summit cone at the north end. Ben Macdui can be climbed equally well from the south by Glen Lui and Glen Derry, or from the north across the Cairn Gorm plateau, but the other two mountains are best climbed from Glen Lui, and the traverse of the three from the south is one of the best day's hillwalking in the Cairngorms, albeit a long one.