Pen-y-Gwryd is a Roman temporary camp whose incomplete ramparts describe a parallelogram of about 224m east-west by 180m, enclosing an area of about 4.0ha. It was recognised from the air in about 1954 (Journal of Roman Studies 45 (1955) 121). Camps such as this were constructed by Roman armies on campaign.

A section was recorded across the line of the southern camp circuit following roadworks in 1968. This showed that the 1.95m wide rampart was turf-built and was fronted by a 0.6m wide berm and a 1.8m wide & 0.4m deep ditch. The ditch-fill was largely of turf-blocks derived from the rampart.

The camp is laid out across the lower western slopes and the marshy floor of one of the most important passes in Snowdonia. Important routes, now followed by main roads, move along the valleys from the east and south, and from the Pass of Llanberis to the west. The camp faces east, the highest point being the north-western angle, set immediately below a prominent crag. The central area, site of the general's tent, altars, podium and place of augury, occupies a distinct hollow.

Sources: RCAHMW Caernarvonshire Inventory II (1960), 31
Webster in the Bulletin of the Board of Celtic Studies 23.2 (1970), 184-6

John Wiles 12.06.07