Someone, at some point in the not-too-distant past, hollowed out the centre of this roughly circular mound of stones and built a crude encircling wall around the hollow, most likely to create a windbreak for shelter. The result is a strange palimpsest: an ancient funerary monument quietly repurposed, the newer stonework visibly cruder and distinguishable at a glance from the older cairn material beneath and around it. The hollow itself measures about 2.6 metres across and drops to a depth of roughly 1.2 metres, carved into what was once a mound around five metres in diameter and standing about 1.5 metres high.

Birreencorragh is the third highest peak in the Nephin Beg range in north-west Mayo, and the cairn sits at the south-western edge of its summit, on ground that straddles the boundary between the townlands of Glendavoolagh and Glendorragha. The mountain falls steeply on either side, down into the valley of Glendavoolagh to the west and Glendorragha valley to the east. This smaller cairn is not alone up here. A short stone bank, about three metres long, connects it to a larger cairn immediately to its south-west, the two monuments sitting in close company where the ridge drops abruptly away to a col. Burial cairns of this kind are generally prehistoric in origin, constructed as funerary or commemorative monuments from heaped stone rather than earthen mounds, and their placement on exposed summits with wide views across the landscape is a recurring pattern in Irish prehistory. Whether those who built this one intended the panoramic position as significant, or simply found the high ground practical, is no longer possible to say.