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The remains of a number of Roman Watchtowers that exist as slight earthworks. The best preserved are Parkneuk (although site is heavily overgrown), Ardunie (trace earthworks only), Kirkhill (best preserved) and Muir-o-Fauld. Kaims Castle is the earthworks remains of a Roman fortlet but the site is fenced off with no routine public access. Ardoch, covered separately on this site, is open to the public and consists of impressive earthworks of the Roman Fort.


Military Deployment. The frontier drew a line between the Highland massif, likely centre of an insurgency, with the rich agricultural lands of Fife and either augmented or replaced the Glen Blocker Forts. It is unclear whether the Legionary fortress at Inchtuthil was still in use when the frontier was established.

Gask Ridge Frontier. Our knowledge of the installations along the frontier is almost certainly incomplete. The known watchtowers and forts are shown above although whether the fortlets were contemporary, or second century AD structures, is unknown.



Ardoch Roman Fort

FK15 9QA

56.267595N 3.876012W

Kaims Castle (Fortlet)

FK15 9LG

56.295235N 3.842289W

Parkneuk Watchtower


56.346056N 3.754247W

Car Parking for:


56.350639N 3.684231W

- Ardunie Watchtower


56.349494N 3.705541W

- Kirkhill


56.350649N 3.672151W

Ca r Parking for:


56.353524N 3.642506W

- Muir o Fauld


56.352144N 3.648847W

Midgate Watchtower


56.366127N 3.586203W

Bertha Roman Fort


56.424825N 3.465097W

Notes: None of the watchtowers are sign-posted for vehicular traffic but are relatively easy to find by following signs to Findo Gask. The footpaths to Ardunie and Muir-o-Fauld are marked. Car Parking options are shown above but on-road parking is also possible with care.

Kaims Castle (Roman Fortlet). Known as Kaims Castle the earthworks of this Roman Fortlet are well preserved. Excavation of the site showed the interior was originally paved but failed to reveal whether the structure dated from the late first century AD. It seems more probable that the fortlet was built concurrent with the construction of the Antonine Wall in the mid-second century AD.

Kirkhill Watchtower. Kirkhill is one of the best preserved towers remaining. The clear view south is highly suggestive that the frontier was intended to maintain a watch in that direction.

Muir-o-Fauld Watchtower. Today the Gask Ridge is covered in tall trees. Whether this was the case in Roman times is disputed but inevitably foliage would have been cleared as required.

Scotland > Perthshire, Kinross, Angus and Fife GASK RIDGE FRONTIER

Following their victory at Mons Graupius in AD 83, the Romans built a chain of forts and watchtowers aimed at separating the Highland massif, likely centre of any insurgency, from Fife. Known as the Gask Ridge frontier, it remained in use for less than a decade before the military withdrew.


Historical Background

The Gask Ridge frontier is a term describing a chain of Roman watchtowers, forts and fortlets built to monitor movement between the Highland massif and Fife. The scheme was constructed by Roman army units in the mid-AD 80s following the campaigns of Gnaeus Julius Agricola in the preceding years. This experienced military commander, a loyal supporter of Emperor Vespasian, had arrived in Britannia in AD 77 having already served in the province (including during the Boudica revolt in AD 60). His first seasons were spent in campaigns against the Welsh and the Brigantes tribe (Northern England) but by AD 80 he invaded deep into Scotland proceeding along the East coast as far as the River Tay. Over the following two years (AD 81-2) Agricola consolidated his advance on the Clyde/Forth isthmus establishing many of the forts later rebuilt for the Antonine Wall whilst concurrently eliminating resistance in Southern Scotland. But by AD 83 he was ready to move north again against the Caledonian tribes who had formed themselves into a confederation headed by Calgacus to repel the invaders. Later that same year he engaged and defeated Calgacus at the Battle of Mons Graupius.

Conquest and Control

Following the defeat of the Caledonians in open battle, the Romans would have had every expectation that they would shift to guerrilla tactics from the comparative safety of the Highland massif. To mitigate against this new threat, and to secure the fertile agricultural land in Fife, the Roman army commenced construction of the military installations that we today associate with the Gask Ridge. It is generally presumed this was a militarised frontier acting in conjunction with the main battle group in the region - the Twentieth Legion (Legio XX Victrix Valeria) - based at the new fortress at Inchtuthil. There remains some debate however on precise timings with a few historians mooting the idea that the Gask Ridge was an attempt to maintain control after the Legionary fortress had been abandoned circa-AD 88.

Military Road

The spine of the frontier was a Roman Road that ran north-west from Camelon to Doune. Thereafter it headed in a north-east direction via Ardoch and Strageath before following an east-north-east path along the Gask Ridge – a strip of land which rises around 70 metres above sea level. It then swung north-east again towards the outpost at Bertha and continued north towards Cargill, Inverquharity and Stracathro Roman Forts. The road seems to have performed a purely military function with the main line of civilian travel/communications taking a slightly more southerly course through Strathearn (the route of the modern A9).


The watchtowers on the frontier were built to a standardised plan. The tower itself was constructed around four timber pillars and probably had wattle and daub walls with rudimentary facilities within. Based on artwork on Trajan's Column (dating from AD 113), it is likely the structure stood around two storeys tall with a viewing platform on the top floor. Surrounding the tower was a square turf rampart, perhaps two metres tall, probably topped with some sort form of breastwork. Surrounding all of this was a circular 'V' shaped ditch (twin ditches on the southern most watchtowers). An earth causeway provided access to the single entrance through the rampart. Although today many of the sites are found in heavily wooded areas, this was not the case in Roman times - and any trees in the vicinity would have been cleared as required to facilitate a clear view.

Whilst the line of the Military Road is quite well understood, precisely where the series of watchtowers started and ended isn't clear. The most southerly known watchtower on the road is at Greenloaning, 1.5 miles south of Ardoch. The most northerly is at Huntingtower, roughly 2 miles short of Bertha. In total 18 watchtowers have been identified to date with spacing between them ranging from 800 metres to over 4,000 metres. It seems almost certain there are more to be found! It is possible the frontier formed a barrier covering the entire gap between the Rivers Forth and Tay and possibly beyond.


Several substantive forts were established on the Military Road - Camelon, Doune, Ardoch, Strageath and Bertha - with their garrisons presumably employed providing the day-to-day policing/security duties required. With the exception of Strageath to Bertha (a distance of around 13 miles), the forts were spaced around 7 miles apart - equivalent to the eventual spacing of the forts along Hadrian's Wall.

In addition to the installations on the Military Road itself, a number of so-called Glen Blocker forts were established. As the name implies, these were built on the primary entry and exit points from the Highland massif. Drumquhassle, Bochastle (Callander), Dalginross and Fendoch were the key forts in the series although it is not clear how long they remained in use. With the threat of insurgency from the Highlands they were all in an exposed position where they could be attacked at comparatively short notice. Bochastle in particular was vulnerable in this sense as it didn't even have full visibility of the Glen it occupied. It is possible then the Glen Blockers were just an interim solution - perhaps occupied for just one Winter - whilst the Gask Ridge frontier was built. Alternatively they could have been designed as forward operating bases for an assault into the Highlands that was later shelved. Either way from a perspective of monitoring access out of the Highlands, the Gask Ridge frontier was actually better placed than the Glen Blockers giving ample time to respond to any approaching enemy force.


Three fortlets are known on the Gask Ridge Frontier - Glenbank (near Dunblane), Kaims Castle (between Ardoch and Strageath) and Midgate Fortlet (adjacent to the Watchtower of the same name) plus one strongly suspected at Raith. Although Kaims and Midgate have been investigated neither have revealed evidence as to their date and it is uncertain whether these were concurrent with the Gask Ridge Frontier system or were later additions, perhaps during the Antonine occupation in the mid-second century AD. Our existing knowledge of such structures seems to suggest they were more common in the later period and the positioning relatively to the main forts is also indicative of a later construction. Furthermore, if they were built concurrently, it seems strange that Midgate watchtower was built as a separate standalone entity just a few metres from the fortlet of the same name. Regrettably, until more fortlets are discovered or more archaeological evidence found, no firm conclusions can be made. All we can assume is that if they were part of the original scheme, their function must have been similar to the Milecastles of Hadrian's Wall - namely small outposts able to support the detached garrisons in the watchtowers.


The precise purpose of the Gask Ridge Frontier is uncertain. Writing in the early third century AD, the Roman historian Cassius Dio informs us that there were two tribal groupings north of the Wall (presumed to be the Antonine Wall) – the Maeatae and Caledonii (Caledonians). This has led to suggestions that the frontier was intended to divide these two factions. If so, it is possible the frontier served in a similar fashion to the German Limes - namely a barrier to control/monitor access. Yet such access across the Gask Ridge, whilst not difficult, has never been the preferred route for armies or traders. Instead the main line of communications was through Strathearn, to the south of the ridge, and which remains the main access today via the modern A9. It may be significant that the Gask Ridge overlooks this route and also that the majority of the watchtowers along its length are offset to the south often partially compromising the northern view. It seems likely then that the watchtowers of the Gask Ridge were actually focused on activity south (towards Fife rather than the Highlands). Perhaps then the function was to monitor any enemy force that penetrated the frontier and ensure Army units were directed into attack. Notwithstanding the above, both Raith and Midgate watchtowers had exceptional views north.

Another, or additional, function mooted was in a signalling/communication role. It seems most probable that some form of communications existed between the facilities although the position of the watchtowers, and questions over the contemporary existence or not of the fortlets, does not provide a clear answer. It is possible that future discovery of ‘missing’ watchtowers, or perhaps installations in the hinterland, may reveal more.

Military Withdrawal

In AD 86 Rome shifted from a four to three Legion policy for Britannia with the Second Adiutrix Legion (Legio II Adiutrix Pia Fidelis) redeployed to Dacia (modern day Moldova). With the removal of the 5,000+ man Legionary force plus a large number of supporting Auxiliary regiments, sustaining an occupation in the difficult terrain of Northern Scotland was no longer viable. The Romans commenced a phased withdrawal ultimately retreating as far south as the Solway-Tyne isthmus where they eventually constructed Hadrian's Wall in AD 122. The Gask Ridge frontier, along with its associated forts, was abandoned no later than AD 90.

Antonine Era

In AD 138 Emperor Antoninus Pius ordered his forces to advance north back into Scotland. Re-establishing themselves on the Clyde/Forth isthmus, there they built the Antonine Wall re-using many of the forts of Agricola's campaigns from the AD 80s. Outposts were also re-established to the north of the Wall along the same Roman Road that had once been the backbone of the Gask Ridge Frontier. The forts of Camelon, Ardoch, Strageath and Bertha were re-established but the dense network of first century AD Roman Watchtowers was not re-commissioned. It is possible the fortlets described earlier were built at this time and performed the same communication/monitoring role. Regardless the Roman presence in Scotland was once again short-lived - by AD 160 they withdrew back to Hadrian's Wall.

Muir-o-Fauld Roman Watchtower

Kirkhill Roman Watchtower

The Gask Ridge seen from near the modern A9, the traditional trade route towards Perth

The view north from near Kirkhill - the flat plateau of the Gask Ridge creates dead ground suggesting the frontier was focused on activity in the south

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