Description
The monument consists of a length of military road approximately 2.5km long, running between Allt Lagan a'Bhainne in the S and Black Burn in the N, part of 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 therafter the route reverted to its former use as a drove road.
Bridges formerly crossed both Allt Lagan a'Bhainne and the unnamed sidestream which joins it approximately 50m downstream. Around here is the area where the construction party made its temporary camp, and traces of this may survive. In this area, the modern track departs from the route of the military road, which ran along an artificial terrace between the two streams. At approximately NH390023 the probable original surface of small cobbles survives.
The area to be scheduled measures 30m wide, centred on the road bed of the military road, running between Allt Lagan a' Bhainne and Black Burn, as marked in red on the accompanying map. It includes the road, ditches and an area which may contain evidence relating to their construction and use.