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Castle O'er, fort and linear earthworks

A Scheduled Monument in Annandale East and Eskdale, Dumfries and Galloway

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Latitude: 55.2237 / 55°13'25"N

Longitude: -3.1931 / 3°11'35"W

OS Eastings: 324199

OS Northings: 592813

OS Grid: NY241928

Mapcode National: GBR 6841.H8

Mapcode Global: WH6X2.XYMT

Entry Name: Castle O'er, fort and linear earthworks

Scheduled Date: 1 April 1924

Last Amended: 13 March 2010

Source: Historic Environment Scotland

Source ID: SM651

Schedule Class: Cultural

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

Location: Eskdalemuir

County: Dumfries and Galloway

Electoral Ward: Annandale East and Eskdale

Traditional County: Dumfriesshire


The monument comprises the earthwork remains of a multi-period, multi-vallate fort and associated linear features, interpreted as boundaries forming part of a land management system. The fort dates from the late 1st millennium BC through to the 1st millennium AD. The monument is located on the summit of Castle O'er Hill, at a height of around 260m above sea level and around 760m west of the White Esk. It is situated in a clearing within recently felled plantation forestry. The fort was last scheduled in 1969 and is being rescheduled to include a previously omitted contiguous length of linear earthwork, and to update the associated documentation.

The visible elements of the monument consist of a number of upstanding, grass-grown earthworks for which archaeologists have identified two main phases of activity. The first phase is a large oval defensive enclosure of two ramparts and a medial ditch. The enclosure is oriented NE-SW and measures around 160m in length by up to around 105m transversely. There are entrance gaps at the SW and NE ends. The second phase is a smaller, single-walled enclosure, contained within the larger, and on the same orientation. The second enclosure measures around 110m in length by up to around 70m transversely. At the W end of the later enclosure the earlier earthworks are reused in refortifying the entrance.

Wrapped around the S and E sides of the monument is a large annexe, defined by an outer bank and inner ditch, also constructed after the initial enclosure. The annexe is around 230m SW-NE with around 25m between the outer extent of the first enclosure and the inner ditch of the annexe. An extension to the annexe, around 80m by 65m in dimension, is located to the west of the annexe's W bank and between the two is a well-defined entrance. An additional entrance to the annexe is located at the NE apex. A linear earthwork, oriented N-S, and comprising a bank and ditch, links into the original bank of the annexe. The length of this linear earthwork can be traced for around 210m to the SE.

Within the interior of the enclosure are the earthwork remains of up to 29 roundhouses of multiple phases of construction. These vary in form from simple to enclosed platforms and single or double ring-groove type. Some of these roundhouses overlie elements of the defensive earthworks and appear to represent a final phase of occupation.

The area to be scheduled is irregular on plan, to include the remains described and an area around within which evidence relating to the monument's construction, use and abandonment may survive, as shown in red on the accompanying map. The scheduled area specifically excludes the above-ground elements of all post-and wire-fences, stiles and the interpretation boards, to allow for their maintenance.

Source: Historic Environment Scotland

Statement of Scheduling

Cultural Significance

The monument's cultural significance can be expressed as follows:

Intrinsic characteristics

This monument represents a complex, multi-period later prehistoric fort with good evidence for multi-phase internal structures. The elevated situation and the enclosing ditches and banks show defensive intent on the part of those who conceived and constructed it. Packing stones protruding through the annexe bank have been interpreted as evidence of a timber palisade, further strengthening the perimeter.

The upstanding nature of the remains, with marked field characteristics, indicate a potential for the good preservation of complex archaeological remains that relate both to the structure of the defences and to internal structural features. These can help us to understand more about the defensive structures and the design, construction, phasing and use of internal dwellings. Localised excavation was undertaken in the 1890s and trial excavation of sections of the annexe ditch in the 1980s but the majority of the monument is apparently undisturbed. The evidence suggests a lack of disturbance in the settlement interior and indicates potential for extensive buried deposits to exist, including both artefacts and ecofacts. These could help us build up a picture of the activities that took place on the site, the physical conditions and the environment and land cover at the time.

The upstanding banks and house footings may contain evidence relating to the creation, use and abandonment of the settlement, helping to inform our understanding of the character of late prehistoric defended settlement including local variations in domestic architecture and building use. This has already been proven to some extent with the recovery of material from the annexe ditch which was subsequently radiocarbon dated. Potential also exists for the survival of buried land surfaces beneath the rampart and other standing features. These could preserve information about the environment before the site was constructed, adding to the time-depth represented by the remains.

Negative features such as post-holes and pits may contain archaeologically significant deposits that can further our understanding of society, ritual, economy, agriculture and domestic architecture and, based on comparative examples, may also include human remains. The presence of occupation remains from different phases has the potential to explore issues such as the duration of house occupation, the nature of abandonment processes and the extent to which occupation of the site was continuous.

Contextual characteristics

The monument lies on the summit of a hill at around 260m above sea level, one of the highest pieces of ground within the vicinity and visibility is good in all directions. The confluence of the Black and White Esk Rivers lies 2.3 km to the south-east and the rivers run N-S in the valleys to the east and west of the fort respectively. Around 740m north-east of the fort is the enclosure of Over Rig, a unique monument with no known comparable sites in the British Isles. Its function has been interpreted as ceremonial and scientific dating has indicated that it was in use at the same time as the fort. Archaeologists do not yet understand the nature of any relationship between the two and the fort retains the potential to further our understanding of this.

The fort is by far the most impressive example of a number of broadly contemporary earthwork monuments in Upper Eskdale, and would appear to form a focus of activity. An unnamed fort, much smaller in scale, lies 1.6 km to the south-west and Bailliehill fort is located 2.7 km to the south-east. Haw Birren settlement is located 1.4 km to the west, and a number of other settlements, most of which are also scheduled, are located nearby (2.6 km to the east, 2.5 km to the south east, 2.3 km to the east, 1.3 km to the WSW, 1.2 km to the east, 1.25 km to the south-east and 850m to the south-east). An unfinished settlement is also located at around 720m to the ENE.

Interpretation of existing survey, excavation and palaeo-environmental information indicates a pastoral economy in an integrated landscape of small and regularly spaced farmsteads on the valleys to either side of Castle O'er. This group of similar settlements in such close geographical proximity have the potential, through further study and comparison, to inform our understanding of settlement patterns in this part of Scotland. Specifically, further study may add to our knowledge of how settlement occurred and changed over time, whether there was expansion or contraction for example, what role the fort played within this pattern and general trends in the construction and abandonment of settlement.

Another significant element of the prehistoric landscape here is the series of linear earthworks, of which the examples directly connected to the fort and included in this scheduling form an integral part. The linear earthworks have been interpreted as part of an extensive cattle ranch with a series of enclosed parks. Related to this system is the annexe at Castle O'er, which may form an element of the cattle handling arrangements. Mapping of the system in the 19th century suggested that the system developed over time, expanding northwards from the fort through a series of intakes, and eventually extended across an area at least 100 ha in extent on the west side of the valley. The lack of contemporary settlement evidence in this particular area of Eskdale would appear to support this hypothesis. The linear earthworks on the east of the valley have also been tied into this system raising the possibility that it extended over a much larger area. Dating of the system is not simple and the relationship between the linear earthworks and other features such as the fort and annexe reinforce the idea that the system developed over a significant period..

The monument therefore appears to be the focus of a cohesive land management system dating to the first millennium AD, long before the first estates are recorded in the historical record and which represents an evolution in land use and division. When compared and contrasted to other elements in this system, and to similar monuments in the region and further afield, there is the potential to significantly add to our knowledge of land division, management, and use in this period. Study into the relationship of the fort and the enclosure at Over Rig could reveal how control over the land was established and maintained. Comparison with similar features such as at Craighousesteads Hill could reveal further information on the scale and character of such systems and reasons for their particular distribution in this part of Scotland. Comparison with evidence of later land division may also establish a significant degree of continuity in the organisation of the prehistoric landscape through into the medieval period, reflected in later land and parish boundaries.

Associative characteristics

William Roy was the first to note the existence of linear earthworks near Castle O'er in the mid-18th century (published in 1793). At that stage they were interpreted as hollow ways. In 1896, a local antiquary named Richard Bell recorded an extensive system of 'trenches' on a map of the Castle O'er estate, now held in Dumfries Museum.

National Importance

This monument is of national importance because it has an inherent potential to inform us of a settlement type that characterises the wider Iron-Age defended domestic landscape, forming an intrinsic element of the later prehistoric settlement pattern in eastern Dumfries and Galloway. This is an outstanding example of such a settlement within a well-preserved prehistoric landscape that includes associated remains of ceremonial monuments and pastoral land management features. The associated linear feature is part of this landscape and directly associated with the fort. The survival of an integrated system has the potential to provide us with a detailed picture of how society of this period may have functioned and how they used and managed their land. Domestic remains and artefacts from Castle O'er have the potential not only to tell us prehistoric architecture, but also about wider society, how people lived, where they came from, who they had contacts with, and may offer an insight into specific functions of the fort, such as defensive episodes or evidence of high status. Old ground surfaces sealed by the ramparts and environmental remains within the ditch may provide information about the nature of the contemporary environment and the use prehistoric farmers made of it. Spatial analysis of this and associated sites may inform our understanding of patterns of landholding and the expansion of settlement. Its loss would impede our ability to understand the placing of such monuments within the landscape both in eastern Dumfries and Galloway and across Scotland, as well as our knowledge of Iron-Age social structure, economy and building practices.

Source: Historic Environment Scotland



RCAHMS records the monument as NY29SW 10, Enclosure, fort and NY29SW 32, Castle O'er Estate linear earthworks. Dumfries and Galloway Council Sites and Monument Record assigns the monument the index numbers MDG7703 and MDG7727.

The monument is currently situated within rough grazing and is surrounded by recently felled forestry plantation and brash.


RCAHMS 1997 Eastern Dumfriesshire: An Archaeological Landscape, Edinburgh: Royal Commission on the Ancient and Historical Monuments of Scotland, 5, 21, 47, 49, 50, 75, 79-86, 161-7, 281, 308, no. 1182.

Barber, J 1999 'The linear earthworks of South Scotland: survey and classification', Trans Dumfriesshire Galloway Natur Hist Antiq Soc. 73, 70, 120-1.

Source: Historic Environment Scotland

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