Megalithic simply means built from large stones, and such structures in Ireland range from portal tombs and passage graves to court cairns and standing stone alignments, most of them raised during the Neolithic or early Bronze Age, roughly between five thousand and three thousand years ago. What exactly this particular structure is, how many stones remain, and how well preserved it might be, remains formally unrecorded in any publicly available source.

Mayo has no shortage of prehistoric stone monuments. The county contains some of the most significant megalithic landscapes in Europe, including the Céide Fields, where an entire Neolithic farming community lies preserved beneath the bog. Roskeen itself is a quiet rural townland, and the presence of a megalithic structure there would be consistent with the broader pattern of prehistoric settlement across the region, where communities chose elevated ground or fertile plains near water and left behind substantial stone constructions that have endured millennia of weather and land use. Without further detail on record, the structure at Roskeen remains a placeholder in the archaeological catalogue, noted and named but not yet fully described.