No signpost marks it, no ruin breaks the skyline, and for decades it appeared on no historic Ordnance Survey maps at all. Yet beneath the grass of Cahercorney, in County Limerick, the ground holds a clear geometric form: two arms of a fosse-like depression, one running roughly thirty metres east-northeast to west-southwest, the other approximately forty metres north-northwest to south-southeast, meeting at a right angle that is far too deliberate to be accidental.

The monument went unrecorded on paper maps entirely until aerial observation began to catch what ground-level survey had missed. It was the Bruff aerial photographic survey of 1986 that first identified the site, logging it as an L-shaped cropmark in image AP 4/3639 from flight Bruff 146. A cropmark forms when buried features, ditches, walls, or disturbances, affect how vegetation grows above them, producing differences in colour or height that are invisible on foot but legible from the air. The Discovery Programme subsequently recorded the same cropmark independently. Later orthoimage surveys confirmed that the earthwork remains physically visible at ground level, appearing in Ordnance Survey Ireland imagery taken between 2005 and 2012, in Digital Globe imagery from 2011 to 2013, and in a Google Earth image dated 5 April 2006. The site lies 770 metres east-northeast of the townland boundary with Loughgur, placing it in the broader orbit of one of the most monument-dense areas in Ireland, and it sits immediately south of a complex of twelve recorded monuments. The record was compiled by Alison McQueen and Vera Rahilly and uploaded in November 2020.

The earthwork sits in working farmland, so access is not straightforward and any visit would require landowner permission. The L-shape and its associated fosse-like depression are most legible in low-angle light, when shadows pick out slight changes in ground level that flatten entirely under a high summer sun. The eastern arm of the form runs alongside a linear field boundary, and that boundary itself may carry older significance than it first appears. Visitors drawn to the wider Loughgur landscape, with its stone circles, lake island settlements, and layered prehistoric activity, might find this quieter, unmapped site a useful reminder that the official record is always catching up.