Clach Mhòr Estate lies in the north-western highlands of Scotland, covering some 48,000 acres, hemmed in by towering mountains, quaking moors and the sea. The name of the estate derives from a very prominent crag near Kinlochy; clach mhòr means “great stone”. The estate is reached by boat from Kylesku, or by long and difficult footpaths: no road connection exists, and the cost of driving a road connection across the surrounding mountains to the nearest road head over 30 miles away would be exorbitant.

Clach Mhòr boasts excellent hunting and river fishing, cultivated lands in Strath Garve, forests, a sawmill, a quarry, a hydroelectric scheme and a small gold mine. A dairy herd grazes the valley floor, while highland cattle summer high in the mountains; sheep are kept too and graze mainly in Gleann Garbh near the head of Strath Garve. The forests supply timber for estate use as well as slow-grown pine sold for use in boat-building. Blocks of attractive pink and blue granite are carved by the local stonemason into prized curling stones. The estate distillery at Clachbeg produces the renowned Clach Mhòr single malt.

Several dozen families live on the estate, engaged in farming, forestry, hunting and general estate duties. Visitors to the estate are frequent: walkers, ornithologists keen to see the eagles, hunters, and anglers.

In 1870 the then Laird of Clach Mhòr, Angus MacTosh, returned from making his fortune in India and sought to build a light railway to serve the estate: the Clach Mhòr Estates Railway (CMER).

Such has been the utility of the railway that it has remained in service ever since.