Easy to miss and easier still to misread as a trick of the terrain, the feature only reveals its character when you know what you are looking at.

A souterrain is a man-made underground structure, typically consisting of one or more stone-lined passages or chambers, built during the early medieval period in Ireland and used variously for storage, refuge, or as a place to keep dairy produce cool. At Rathcaled, the collapse of such a structure has left two depressions aligned in a rough cross shape: a longer one running east-northeast to west-southwest, measuring about 14.7 metres in length and roughly a metre deep, and a shorter one running north-northeast to south-southwest at around 9 metres. Together they sit in the western part of a ringfort, the circular earthwork enclosure that would have been the farmstead or settlement to which the souterrain originally belonged. Ringforts, of which thousands survive across Ireland, were typically the homes of farming families during the early medieval centuries, and the presence of a souterrain within one is a fairly common arrangement, though the Rathcaled example is now unusually legible in its collapsed state. The Irishtown River runs roughly 140 metres to the south, marking the boundary with the neighbouring townland of Paddinstown Lower, and the hilltop position means the surrounding landscape opens up in every direction, the kind of elevated ground that would have suited both the practical needs and the social signalling of an early medieval household.