Yet this slight rise in the low-lying grassland of Castletroy, sitting roughly forty metres west of the Mulkear River where it marks the boundary between the townlands of Castletroy and Ballyvollane, is believed to be a ring-barrow, a prehistoric burial monument typically consisting of a central mound or grave enclosed by a circular bank and ditch. What makes this particular example quietly remarkable is not its visibility but its near-invisibility. It appears on no Ordnance Survey mapping, not on the 1840 six-inch series nor on any revision since, meaning it existed entirely outside the official cartographic record for well over a century.

The site first came to archaeological attention in 1990, when Celie O'Rahilly described a circular feature defined by a very low bank of around thirty metres in diameter, with a depression at its centre that appeared to have been recently infilled with clay. Two decades later, an assessment carried out by Aegis Archaeology Ltd. in 2009 and 2010 returned a more nuanced picture. The team found the platform still visible, gently sloping at its edges, but noted no clear trace of the bank O'Rahilly had recorded. A depression survived in the north-east quadrant, measuring roughly three metres by two metres and about thirty centimetres deep. A possible ditch was traced from south through east to north-west, averaging three metres wide and detectable in places only as a strip of noticeably greener vegetation than the surrounding field, a phenomenon sometimes called a cropmark, where buried features influence how plants grow above them. The ditch's western side could not be defined at all due to flattened long grass. A Google Earth image taken in 2018 confirmed faint sub-circular cropmarks at the location, lending further quiet weight to the identification.

Because the site sits in ordinary agricultural grassland with no public monument signage, a visit requires some prior orientation. The archaeology.ie record for the site notes that the mapped location has historically been plotted slightly too far north, so cross-referencing the cropmark visible on satellite imagery is more reliable than relying on the national database pin alone. The best conditions for spotting the platform's slight elevation are in low winter or early morning light, when shadows throw even modest ground variations into relief. The greener vegetation marking the probable ditch line is most legible in dry summer conditions, when differential moisture retention in disturbed soil makes buried features readable from above.