A small earthwork in the townland of Cahercorney, County Limerick, was identified only because a low-flying aircraft happened to pass over at the right angle, at the right time of day, catching a shadow that ground-level observation would never reveal. By the time anyone looked again with satellite imagery, it was gone entirely from view, absorbed back into the improved wet pasture that surrounds it.

The monument was first recorded during the Bruff aerial photographic survey in 1986, when survey image 296.1 captured what appeared to be a small penannular earthwork, that is, a roughly circular enclosure with a deliberate gap or opening, in this case facing south. Penannular enclosures are a recurring form in the Irish landscape, associated broadly with early medieval settlement and agricultural organisation, though their dates and precise functions vary considerably from site to site. This particular example sits in low-lying improved pasture, about 40 metres north-east of a watercourse that also serves as a townland boundary with Loughgur, a locality already well known for its concentration of prehistoric and early historic monuments. Two further enclosures lie within a few metres to the south-east and south respectively, suggesting the area once held a cluster of related features. Notably, the monument does not appear on any Ordnance Survey Ireland historic maps, meaning it left no trace in the cartographic record even before it was levelled. Subsequent examination of ortho-imagery taken between 2005 and 2013, and again on a Google Earth image from September 2020, confirmed that nothing of the earthwork remains visible at the surface. The record was compiled by Alison McQueen and Vera Rahilly and uploaded in November 2020.

There is little a visitor could hope to see here in any conventional sense. The field gives nothing away. Its value now is almost entirely archival, residing in the 1986 aerial photograph that briefly caught the enclosure before agricultural improvement erased its surface expression. For those interested in the wider landscape, the proximity to the Loughgur townland boundary is worth keeping in mind, since the broader area around Lough Gur contains one of the densest archaeological landscapes in Munster, and features in that vicinity do occasionally reward careful walking in low winter light when slight earthworks can reappear as faint shadows across grass.