That absence is quietly telling. Most ancient structures of this kind were recorded by the OS during the nineteenth century, so a site that escaped that net has a particular kind of obscurity about it, one that speaks less to recent discovery than to how easily the countryside can keep its own counsel.

The structure at Drumguillew is a court tomb, a type of megalithic burial monument built in Ireland during the Neolithic period, roughly four to six thousand years ago. Court tombs are typically characterised by a roofless forecourt area opening into a covered gallery where the dead were placed. Here, the gallery is slightly curved rather than strictly linear, running approximately five metres in length and just under one and a half metres wide, aligned on a roughly northwest to southeast axis. A single standing stone to the southeast of the gallery has been identified as a probable court stone, the kind of upright that would once have helped define the ceremonial open space at the entrance. Several of the stones are shattered, which may reflect deliberate destruction at some point in the past, the effects of agricultural clearance, or simply the slow attrition of millennia. The monument was documented in the Archaeological Inventory of County Monaghan, published in 1986, and subsequently revised by Michael Moore in 2018.