The Lairig Ghru is one of the classic mountain passes in Scotland, a deep glacial trench cutting through the heart of the Cairngorm plateau from Aviemore in the north to Braemar in the south. The full crossing covers about 30 kilometres and gains 840 metres at the high point, typically taking eight to ten hours for fit walkers. Most people do it as a single long day with a car shuttle; some camp at the Corrour Bothy near the southern end.
The pass itself is a dramatic geological feature — a narrow, boulder-filled valley between the western Cairngorms and Ben Macdui, with vertical walls on both sides at the narrows. The Pools of Dee, small lochs at the summit of the pass, freeze solid in winter. The boulderfield below them is serious walking country. This is not a stroll — proper boots, waterproofs, and navigation skills are required, and the plateau above has claimed lives in bad weather.