The A831 is a loop road to the village of Cannich, and not a direct end-to-end route.
Drumnadrochit - Cannich - Beauly
The road starts in Drumnadrochit (home of Loch Ness Monster exhibitions) where the A82 takes a sharp turn over the River Enrick. A mile out of Drumnadrochit it bypasses the hamlet of Milton (which is on the old single-track road) and meets the A833, which is a much shorter road to our final destination of Beauly. The A831, however, continues ahead up the heavily wooded Glen Urquhart. The road is double-track and twisting, with some fairly tight bends and only a few straight sections. There are scattered houses and occasional views of fields, but mostly the scene is deciduous woodland, with conifer plantations on the valley sides. Half way up the glen at Balnain there is an attractive small loch, Loch Meikle. After the Corrimony junction the road climbs more steeply, and leaves the trees to run through moorland and rough grazing for a mile or two. Here the remains of the old single-track road can be seen just to the north.
At the top of the hill the route is in coniferous forest but with an open view straight ahead to the mountains of Glen Affric and Glen Cannich. From here the road descends steadily but steeply into Strathglass, and at the foot of the hill it narrows and turns sharply to cross the River Glass and the flat valley bottom to reach Cannich, 12 miles from Drumnadrochit. Cannich has a caravan site and a Youth Hostel. From the crossroads in the village a minor road runs to Glen Cannich where it ends at Loch Mullardoch's hydro-electric dam, and another road runs to Glen Affric, which is famous for its native pine woods, lochs and mountain scenery. An unsurfaced road and then a footpath continue through the upper part of Glen Affric to cross eventually to Morvich on the west coast. This is a spectacular route through remote country, and every year on the Saturday closest to midsummer it is the route of the Highland Cross charity biathlon (Morvich to Beauly - 20 miles running or walking, and 30 miles cycling), so from Cannich the A831 forms part of the Highland Cross cycling route.
In Strathglass the road is only just wide enough for two cars, but almost level. It follows the edge of the strath (valley), with wooded hills rising on the left. The valley floor is farmland and there are only a few houses. At Struy there is an inn and a stone bridge across the River Farrar. A few miles later the road once again becomes properly double-track - a welcome point for Highland Cross cyclists as it means the end is not too far now. A sharp rise after Aigas golf course is followed by a downhill section; here the river (now called the Beauly) flows through a picturesque gorge with a small hydro-electric dam. A mile or so later the road climbs through a little dry valley with grassy sides (a glacial meltwater channel) before dropping into the more open farmland of Kilmorack. Around here, minor roads lead up the valley side to more farms and scattered houses. After Kilmorack there is a short, sharp descent to the junction with the A862 (formerly the A9). This is the end of the A831, but for the Highland Cross cyclists there is one mile more to go to the finishing line and cheering crowds in Beauly Square.