Description
The monument consists of a length of military road approximately 4.5km long, running between Allt Lagan a'Bhainne at the N and the watershed at the S, part of the the road built between Dalwhinnie and Fort Augustus in 1731, under the direction of General Wade.
By 1730, the military roads from Dunkeld to Inverness and along the Great Glen were complete, and in order to link Fort Augustus directly to the first of these a road was planned, running partly along the upper Spey valley and climbing to 800m at the Corrieyairack Pass to cross the watershed. The new road was 45km long. Work was started in April 1731 and completed by the end of that October, at a cost of L3281 4s 9d. Some 17.5km of this road remains unmetalled.
The road was intended to be constructed of layers of rammed stones, with large stones at the base, topped by smaller ones, to a depth of over a metre. In stretches with firm subsoil, however, this is likely to have been reduced. In places can be seen patches of flat stone cobbles, which may be remains of the original surface, but for much of its length the road is likely to have been surfaced with gravel. Wherever the terrain allowed the road was flanked by a ditch on the uphill side (and in parts on the downhill side), and a further uphill ditch appears in some places, either parallel to or in place of the roadside ditch, approximately 8m from the edge of the road.
The road was abandoned north of Laggan in 1830, and thereafter the route reverted to its former use as a drove road.
The bridge over Allt Coire Uchdachan still stands, and there are traces of the bridge over Allt Lagan a' Bhainne. Both were single- arched structures with low parapets and without any significant humped back.
The area to be scheduled measures 30m wide, centred on the road bed of the military road, running between Allt Lagan a' Bhainne and the watershed, as marked in red on the accompanying map, to include the road, ditches and an area which may contain evidence for their construction and use.