A large Roman marching camp has been confirmed in the vicinity of Usk, Monmouthshire, during archaeological aerial reconnaissance by the Royal Commission in 2009 and 2011. The Llancayo Farm Roman marching camp measures 500m north-south by 400m east-west, and thus encloses approximately 20.2 hectares. There are only five Roman marching camps in Wales and the Marches between 12-20ha in size, and only three examples greater than 20ha (Davies and Jones 2006, 57). The camp was first identified when cropmarks of the north-eastern ditch and rounded corner were recorded during Royal Commission aerial reconnaissance on 9th July 2009. Only during a further flight on 26th April 2011 were cropmarks of the south-west corner of the camp recorded, allowing a full assessment of its shape and extent. As yet there is no evidence for the positions of the gateways.

The camp is sited to make full use of the central and northern part of a broad alluvial terrace which rises gently from 22m-30m above O.D., set within a wide meander of the river Usk. The camp lies some 3km north-west of the Roman legionary fortress at Usk and is the first marching camp to be recorded in the county of Gwent. It is probably of pre-Flavian date (Burnham and Davies (eds) 2010, 38), and raises the possibility of further discoveries in this region of south-east Wales.

The choice of siting of this Roman camp is of considerable interest. It entirely encloses the Gwehelog Roman temple (NPRN 405805; Driver 2009, 76-8; Wellicome 2010), which may have developed from an earlier Iron Age shrine. In addition, the northern ditch of the Roman camp neatly bisects a large circular enclosure which forms part of a wider early Bronze Age barrow cemetery (NPRN 409179); the cutting of the larger circular enclosure by the Roman ditch suggests that this prehistoric monument was either plough-levelled by Roman times or was originally constructed as an open enclosure. There are clear parallels with the three adjacent marching camps at Walton in Radnorshire, two of which bisect an undated circular enclosure (NPRN 401217). The position of the Llancayo Farm Roman marching camp, enclosing a Roman temple complex on the possible site on an earlier Iron Age shrine, is highly significant and suggests considerable purpose behind its choice of siting.

Royal Commission aerial reconnaissance on 22nd July 2013 discovered a second Roman marching camp in Gwent, at Killcrow Hill near Caerwent (NPRN 419220).

Toby Driver and Oliver Davis, RCAHMW. 26th May 2011

References:
Burnham, B.C. and Davies, J.L. (eds.), 2010. Roman Frontiers in Wales and the Marches, RCAHMW.
Davies, J.L. and Jones, R.H. 2006. Roman Camps in Wales and the Marches, University of Wales Press, Cardiff.
Davis, O. and Driver, T. 2015, Llancayo Farm Roman Marching Camp, Usk, Monmouthshire, Archaeologia Cambrensis 163 (2014), 173-184
Driver, T. 2009. RCAHMW Aerial Reconnaissance 2009, Archaeology in Wales 49, 73-82.
Wellicome, T, 2010, SMR/HER enhancement project for: Gwehelog/Llancayo Roman Temple, Coursework project for the University of Bristol, MA in Landscape Archaeology. Unpublished.