The stone at Derryorgan in north County Cork was absent from the Ordnance Survey six-inch maps of both 1842 and 1905, meaning that for the better part of two centuries of systematic Irish cartography, it simply did not officially exist. It stands in pasture on a gentle west-facing slope, leaning slightly to the south-south-west, and measuring 1.7 metres in height with a roughly square cross-section of 0.8 by 0.8 metres. Its long axis runs north-east to south-west, a directional alignment that recurs across many Irish standing stones, though whether this reflects deliberate astronomical intent, practical convenience, or something else entirely remains a matter of ongoing debate.

The stone is irregular in plan, meaning it has no cleanly geometric shape, which is fairly typical of the type. Standing stones, sometimes called galláin in Irish, were erected throughout the Bronze Age and into the early Iron Age, and their purposes were various and are still not fully understood. Some mark boundaries, some cover burials, some appear to stand in deliberate relationship to the wider landscape. Without excavation or associated finds, the Derryorgan stone keeps its particular reasons to itself. Its absence from nineteenth and early twentieth-century mapping is not necessarily evidence that it was unknown locally; the Ordnance Survey's six-inch series, comprehensive as it was, did not capture every ancient monument, and many were simply overlooked in the field or considered too ambiguous to record confidently.