The B8079 follows, for its entire length, the former course of the A9 from Garry Bridge to Bruar west of Blair Atholl.
The route starts at a T-junction with the B8019 at Garry Bridge, with that route continuing south along the old A9 to Pitlochry. Heading north, the B8079 immediately plunges into the Pass of Killiecrankie, with the new A9 route high up to the right in the trees on the Pass of Killiecrankie Viaduct. An unsigned driveway on the left is the former terminus of the B8019 climbing up from the old Garry Bridge. Four routes run parallel through this narrow defile: there's the river far below, then the railway line alongside the B8079, with the A9 high above. The route continues north, running through the trees on some reasonably long straights, the road being wide and well aligned as befits the former A9.
Before long, the Killiecrankie Visitor Centre is reached, after which the road drops steeply down into Killiecrankie village, continuing to lose height as it winds past the houses. Beyond the village, a long straight running alongside the railway line takes the road through Aldclune – with an older alignment on the right in places showing how the road was improved when it was still the A9. Beyond Aldclune, the B8079 passes under the current route of the A9, which also crosses the railway and River Garry on a substantial 4-span viaduct. Soon after, a right turn (a spur of the B8079) provides a link between the old and nethe roadus across the River Tilt in the middle of the village, and then past the castle entrance.
Coming out of the village, the road turns onto another long straight running between the railway line and the wall of the Castle Estate. After perhaps a mile and a half, with just a couple of slight kinks, the road turns sharp left then right to pass under the railway, but soon resumes a straight, albeit undulating, course into Bruar. Bruar itself is hardly a village, just a place name with a bridge over the Bruar Water and the now famous House of Bruar retail destination, which draws customers from across Scotland, if not the world. This is also, far more importantly, the end of the B8079. It meets the end of the B847 and continues on a few more yards to its terminus on the A9.
Being the original route of the A9, the B8079 has a long history, dating back centuries. The route was already well used by drovers, cattle rustlers, and the few people who needed to travel through Highland Perthshire in 1725 when General Wade first planned his military roads. His route was completed by 1728, stretching from Dunkeld to Inverness, and in places is still followed by the B8079 today. A century later, the road had been upgraded by the county, following the works carried out by Thomas Telford to the north, and apart from some small improvements (such as that noted above at Aldclune) the road remains much the same today.
The military road
The B8079 appears to follow Wades line pretty closely from Garry Bridge north through Killiecrankie. However, on the approach to Blair Atholl, the old military road forks left across the fields, passing the church as it takes a straight line to the Old Bridge of Tilt. It can then be traced around the north of Blair Castle, and continuing through the estate, before petering out under later landscaping. The last mile or so, running along between the railway and river to Bruar appear to be back on the old route. For more detail, see the A9/Drumochter Pass page.