Offa's Dyke: section 650m east of Cwm-sanaham


Heritage Category: Scheduled Monument

List Entry Number: 1020906

Date first listed: 23-Feb-1933

Date of most recent amendment: 15-Apr-2004


Ordnance survey map of Offa's Dyke: section 650m east of Cwm-sanaham
© Crown Copyright and database right 2018. All rights reserved. Ordnance Survey Licence number 100024900.
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This copy shows the entry on 16-Dec-2018 at 07:52:58.


The building or site itself may lie within the boundary of more than one authority.

District: Shropshire (Unitary Authority)

Parish: Llanfair Waterdine

National Grid Reference: SO 27205 75470


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

Offa's Dyke is the longest linear earthwork in Britain, approximately 220km, running from Treuddyn, near Mold, to Sedbury on the Severn estuary. It was constructed towards the end of the eighth century AD by the Mercian king Offa, and is believed to have formed a long-lived territorial, and possibly defensive, boundary between the Saxon kingdom of Mercia and the Welsh kingdoms. The Dyke is not continuous and consists of a number of discrete lengths separated by gaps of up to 23km. It is clear from the nature of certain sections that differences in the scale and character of adjoining portions were the result of separate gangs being employed on different lengths. Where possible, natural topographic features such as slopes or rivers were utilised, and the form of Offa's Dyke is therefore clearly related to the topography. Along most of its length it consists of a bank with a ditch to the west. Excavation has indicated that at least some lengths of the bank had a vertical outer face of either laid stonework or turf revetment. The ditch generally seems to have been used to provide most of the bank material, although there is also evidence in some locations of shallow quarries. In places, a berm divides the bank and ditch, and a counterscarp bank may be present on the lip of the ditch. Offa's Dyke now survives in various states of preservation in the form of earthworks and, where sections have been levelled and infilled, as buried features. Although some sections of the frontier system no longer survive visibly, sufficient evidence does exist for its position to be accurately identified throughout most of its length. In view of its contribution towards the study of early medieval territorial patterns, all sections of Offa's Dyke exhibiting significant archaeological remains are considered worthy of protection.

The section of Offa's Dyke 650m east of Cwm-sanaham survives well, despite some reduction by ploughing, and will retain evidence for its construction as well as artefactual information relating to its use over time. In addition, environmental evidence, in the form of organic remains, will survive within the fill of the ditch and in the buried ground surface below the bank and counterscarp bank. This will provide information relating to the landscape within which the Dyke was constructed.


Legacy Record - This information may be included in the List Entry Details.


The monument includes the buried and earthwork remains of a section of the linear boundary known as Offa's Dyke, 650m east of Cwm-sanaham. Offa's Dyke generally consists of a bank, up to 3.5m high, with an intermittent ditch and quarry pits in places. It was strengthened in some areas by additional earthworks, namely a berm between the bank and ditch and a counterscarp bank on the outer lip of the ditch.

In this section, the Dyke runs for some 1.5km through a steep ravine in its central part. This topography has caused difficulties in its construction, requiring the usual form of the Dyke to be modified.

At its northern end, the Dyke has been reduced by ploughing but is visible as a slight continuous rise in pasture as far as the crest of the west shoulder of Cwm-sanaham Hill.

Towards the central part of this section, the Dyke runs through the upper part of the ravine above Cwm-sanaham, and here the bank runs along the crest of a rocky outcrop as far as a gap made for farm traffic. The Dyke then continues as a terrace in the side of the hill where the current footpath runs along the line of the infilled ditch. Further south the Dyke is visible for 200m as a degraded bank and ditch with traces of the counterscarp bank. The Dyke in this southern section is 18m wide from the edge of the bank to the western edge of the counterscarp bank. The bank is about 1.5m high at its highest point.

Further sections of Offa's Dyke 220m to the north and immediately to the south are the subject of separate schedulings.

All fence posts, stiles and gates are excluded from the scheduling, although the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

Legacy System number: 32607

Legacy System: RSM


Books and journals
Fox, C, Offa's Dyke, (1955), 137
Kay, K, Richards, , Offa's Dyke Path North, (1995), 18

End of official listing