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Cof Cymru: National Historic Assets of Wales · Wales

Roman Marching Camp South East of Coelbren Fort

Onllwyn, Neath Port Talbot, Wales

The record

Designation
Scheduled monument
Site type
Marching Camp
Period
Roman
Community
Onllwyn
Unitary authority
Neath Port Talbot
Country
Wales
Coordinates (centre of the scheduled area)
51.77953, -3.65102
SAM number
GM343
Cadw record number
1011

Slide toward Today to fade the historical sheet and see the modern map underneath.

David Rumsey Map Collection, Stanford Libraries

Shown on 5 historical map sheets, the earliest the 1636 "Cornubia : Devonia, Somersetus, Dorcestria, Wiltonia, Glocestria ..." (David Rumsey Map Collection, Stanford Libraries).

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This record in Cadw's own full report ↗

Cadw's description

The following provides a general description of the Scheduled Ancient Monument.

The monument comprises the remains of a Roman marching camp, probably constructed during the period of Roman conquest (AD74-78). The large embanked enclosure is typically playing-card shaped and occupies part of a broad low ridge which rises to approximately 230m OD. The camp is bounded on all sides except the east by the marshy valleys of the Camnant and Afon Pyrddin. The crest of the ridge runs almost due west from the south-east corner so that most of the interior of the camp falls gently to the north and overlooks the neighbouring Roman fort at Coelbren. The marching camp and fort are about 180m apart.

The camp is 438m long, tapering from 332 to 305m, the area being about 14 hectares. Where best preserved, in the southern half of the west side, the defences consist of a bank and ditch about 4.6m wide by 0.3m high overall, but for most of the circuit except in the south-west quarter they have been damaged by the construction of field banks on or very near their line. The rampart can be detected almost throughout the circuit, and the rounded corners (except the south-west) remain recognisable; but all details of the entrances have been destroyed.

The monument is of national importance for its potential to enhance our knowledge of the Roman conquest of Wales. The monument retains significant archaeological potential, with a strong probability of the presence of archaeological deposits and environmental and structural evidence. The monument forms an important element in the wider Roman landscape.

The area scheduled comprises the remains described and an area around them within which related evidence may be expected to survive.

Nearby in the register

Other entries of the same register within about three miles of this one, by straight line.

Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), 2026-09-07, licensed under the Open Government Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Cadw, the Welsh Historic Environment Service · Open Government Licence v3.0
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