Pentre Camp is an oval, multivallate, contour hillfort, measuring c.74m by 48m, enclosing a mere 0.8 acres. Its defences comprise five ramparts, now largely reduced to terraces on all but the north and west, where only three ramparts appear to have been constructed. The entrance is in the east where the third and fourth ramparts are linked to form an entrance passage. There is now no evidence of any huts within the enclosure. (OS Record card entry, 1972).

A field visit by T. Driver on 14th March 2007 confirmed the above details in addition to those revealed during the original site survey:

The hillfort was carefully and expertly planned and built to achieve a final plan which is difficult to parallel in other parts of central Wales, although mulitvallate sites are common. As well as the main concentric ramparts, there are traces of discontinuous and more denuded interim ramparts on the south and west sides, suggesting more than one phase of development. The earthworks are low now, and are crossed by deeply-gouged parallel field drains. Whether they ever stood very high is uncertain; it is possible that these banks provided firm foundations for concentric timber defences.

Interesting aspects of the rampart construction are revealed on the north side, where historic field boundaries cross the line of the Iron Age outer ramparts. On the north-east side, at SJ 1179 0963, an area of eroded ground crossed by a field bank reveals a high proportion of boulders, suggesting that these made up the original rampart structure. On the north side, at approx. SJ1174 0963 there is an isolated stretch of stone walling in the present field boundary where it crosses the Iron Age rampart; again, there is the possibility that this is a fragment of the original rampart revetment.

The most significant aspect of the site's setting and topography is the very prominent spring head below the fort to the north at SJ 1168 0966. This deep, enlarged spring head which is backed by a rocky slope and is still issuing water, sits immediately at the base of the precipitous slopes which fall from the north side of the hillfort. Although enlarged and lined with brick in historic times, it is reasonable to assume that the site of this spring was important in the choice of siting of the hillfort, at least for practical reasons. There is a high probability that artefacts from the hillfort have rolled down into the spring in prehistory and may be preserved in waterlogged conditions. Whether the spring had any symbolic role in the life of the hillfort inhabitants is more speculative.

T. Driver, 20 March 2007.