Ancient Monuments

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Cnoc an Duin fort, 1250m WNW of Coag

A Scheduled Monument in Tain and Easter Ross, Highland

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Latitude: 57.7625 / 57°45'45"N

Longitude: -4.1923 / 4°11'32"W

OS Eastings: 269669

OS Northings: 876871

OS Grid: NH696768

Mapcode National: GBR J806.JDX

Mapcode Global: WH4F4.K5X0

Entry Name: Cnoc an Duin fort, 1250m WNW of Coag

Scheduled Date: 25 July 2023

Source: Historic Environment Scotland

Source ID: SM13774

Schedule Class: Cultural

Category: Prehistoric domestic and defensive: fort (includes hill and promontory fort)

Location: Logie Easter

County: Highland

Electoral Ward: Tain and Easter Ross


The monument comprises the remains of a fort dating to the Iron Age (800 BC – AD 400) on Cnoc an Duin. It survives as the low drystone remains of two incomplete circuits of outer and inner walls, as well as buried features. The walling encloses an area approximately 200m east northeast to west southwest by 80m transversely. Sections of inner and outer low drystone walling are visible in the north, south and west quadrants. At the east end, a steep gully provides a natural defence. The fort occupies a roughly level area of rough ground on the summit of Cnoc an Duin, at 270m above sea level. 

The scheduled area is irregular. It includes the remains described above and an area around within which evidence relating to the monument's construction, use and abandonment is expected to survive, as shown in red on the accompanying map. 

Source: Historic Environment Scotland

Statement of Scheduling

The national importance of the monument is demonstrated in the following way(s) (see Designations Policy and Selection Guidance, Annex 1, para 17): 

a.  The monument is of national importance because it makes a significant contribution to our understanding as an example of an Iron Age hilltop defended enclosure or fort. It adds to our understanding of Iron Age society in northern Scotland and the function, use and development of forts and other defended sites.  

b.   The monument retains structural attributes which make a significant contribution to our understanding or appreciation of the past. The survival of sections of outer and inner drystone walling with entrance details can help us understand more of the construction techniques used and phasing of the site. There is good potential for the survival of additional archaeological and environmental evidence below the walling and in the buried soil horizons.   

d.   The monument is a particularly good example of an Iron Age hilltop enclosure or fort, where the twin, eccentric circuits of walling were not completed or, where other materials and techniques were used to complete these circuits but the evidence of this is not visible. It is therefore an important, less-common example of an Iron Age fort in Scotland. 

e.   The monument has research potential which could significantly contribute to our understanding or appreciation of the past. It can tell us about the ways in which landscape and territory are marked by prominent constructions. It can help us understand how the construction of such a fort was prepared and the initial works undertaken. The intermittent nature of both walling circuits points to either an unfinished example or possibly one where alternative materials such as timber were used to complement the drystone structures. The possible alternative development sequences and the reasons behind them adds considerably to our interest. Excavated examples have confirmed the research value of these monuments. 

f.   The monument makes a significant contribution to our understanding of the historic landscape. It occupies the summit of the locally prominent Cnoc an Duin, it would have controlled routing along this section of Strathrory and it has commanding views to the west, northwest, east and southeast. 

Assessment of Cultural Significance

This statement of national importance has been informed by the following assessment of cultural significance:

Intrinsic characteristics (how the remains of a site or place contribute to our knowledge of the past)

This Iron Age fort (800 BC – AD 400) was positioned and constructed to exploit local terrain. The summit of Cnoc an Duin is an area of relatively level ground, with strong natural defences. It is protected by a steep craggy slope across the south side of the hill and at its east end by a steep gully. Towards the outer edge of the summit, there are at least four intermittent sections of low drystone walling cut into the slope and contouring around the south, west and north sides of the hilltop.  This walling encloses an area of approximately 2.2 hectares.  An entrance is visible at the west side of this outer wall, where facing stones are seen on the wall return. Research suggests there may have been a second entrance towards the east side. There is a second, inner wall with three sections visible along the west, north and east sides. This wall is up to 1.2m high and up to 3.8m wide and there is evidence of an entrance on the west side and possibly a second entrance towards the east side. The only visible feature within the interior is a shallow, stone-lined depression.

The archaeological and research potential of the fort is indicated by the presence of substantial, surviving works to enclose the hill summit and the associated archaeological and environmental remains that are likely to survive in the buried soil horizons. The field remains of two circuits of defensive stonework survive to a marked degree. There are construction trenches, quarry pits and piles of stone as well as the upstanding remains  of walling along two eccentric circuits. These remains can help us understand the techniques and sequence of construction as well as providing a comparator with other, similar sites. The position and detail of the entrances can help us understand how the fort was intended to function. These works are likely to seal environmental remains which can help us understand more of the contemporary climate and land cover.

The intermittent lengths of completed walls, the areas of piled stone material and the contention that the inner wall was meant to form a completed circuit have led to the interpretation that it is an incomplete and only partially used or abandoned site (Feachem, 1971). The excavation of similar sites (such as at Durn Hill, Aberdeenshire, Canmore ref 17973) however, raises the possibility that areas of absent walling may have been filled by a timber palisade. This monument is therefore of significance as a less common form of later prehistoric defensive hilltop enclosure, where its final form was never realised or where a blend of defensive constructions and materials were used. Finally, the inner wall follows a different circuit to the outer wall and researchers have suggested this may represent time-depth indicating a different, possibly later, phase of construction.  

Contextual characteristics (how a site or place relates to its surroundings and/or to our existing knowledge of the past)

The fort belongs to a wide class of later prehistoric / early historic defended enclosure or fort, with more than 1600 examples known of in Scotland. Examples closest to Cnoc an Duin include two forts on the inner Dornoch Firth (Canmore IDs 13066, 13808, scheduled monument SM1856), the fort at Tarbat Ness (Canmore ID 15627, scheduled monument SM4806) and at Easter Rarichie on the Nigg peninsula (Canmore ID15300, scheduled monument SM5215).

Cnoc an Duin fort it believed to belong to a much less common subset of Iron Age forts, described as unfinished forts (Feachem,1971, Lock & Ralston, 2017). A review of sites where similar characteristics are found – twin partial ramparts where the defensive works appear incomplete, reveals eight comparable examples in Scotland – at Maxwellston in South Ayrshire (Canmore ID 62566, scheduled monument SM2201), at West Lindsaylands in South Lanarkshire (Canmore ID 48665), at Craig Hill in Dumfries and Galloway (Canmore ID 67649, scheduled monument SM12740), at Witches Knowe in East Lothian (Canmore ID 56202, Scheduled Monument SM5861) and four examples in Scottish Borders by Peebles, Stagebank and Butchercote (Canmore IDs 51281, 51471, 54638, 57242, scheduled monument SM2715, SM3028). Recent excavations at Durn Hill fort in Aberdeenshire (Canmore ref 17973, SM13748), have shown however, that apparently unfinished drystone wall circuits at such sites could be complimented by timber palisades. This monument is therefore a representative example of a fort with discontinuous stone defences. It can help us understand more of the context to defended enclosures in Scotland, how they developed and the reasons for their abandonment. This example in particular can help us to understand why some forts appear not to have been completed, and if this was in fact the case.

Later prehistoric forts are often sited on rocky knolls and ridges for defence as well as for territorial visibility in the wider landscape. The terrain over Cnoc an Duin provides for natural defence on its eastern and southern sides while the inner and outer walling protects the easiest approach, from the north. The fort has been deliberately sited to take advantage of the terrain as well as its prominent position in the landscape, dominating lower ground to the south along Strathrory and with commanding long-distance views to the west, northwest, east and southeast over the Cromarty Firth. It has an interesting proximity to a local cluster of near-contemporary settlement and agricultural activity – a cluster of prehistoric houses and cairnfields within 1km to the southeast (Canmore ID 14552, scheduled monument SM3754). It can therefore help us understand the broader prehistoric exploitation of landscape and how communities managed land and natural resources in a particular locale.

Associative characteristics (how a site or place relates to people, events, and/or historic and social movements)

There are no known associative characteristics that contribute to the monument's national importance.


Source: Historic Environment Scotland



Historic Environment Scotland reference number CANMORE ID 13710 (accessed on 19/05/2023).

Local Authority HER/SMR Reference MHG8188 (accessed on 19/05/2023).

Feachem R W, 1971, Unfinished hill-forts, in Hill D, and Jesson M, The Iron Age and its hill-forts: papers presented to Sir Mortimer Wheeler on the occasion of his eightieth year. Southampton

Lock G, and Ralston I, 2017, Atlas of Hillforts of Britain and Ireland. [ONLINE] Available at:

RCAHMS, 1979, The archaeological sites and monuments of Easter Ross, Ross and Cromarty District, Highland Region, The archaeological sites and monuments of Scotland series no 6. Edinburgh.


HER/SMR Reference


Source: Historic Environment Scotland

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