In the flat pastureland of Glenogra, County Limerick, close to the boundary where the townland meets Coolfune, a low earthen enclosure was captured from the air in 1986 and has stubbornly refused to show itself since. It does not appear on Ordnance Survey Ireland's historic maps. It did not register on aerial orthoimages taken between 2005 and 2012, nor on Digital Globe imagery from 2011 to 2013, nor on Google Earth images taken as recently as June 2018. For all practical purposes, the site is invisible to every instrument trained on it, except for one survey photograph taken nearly four decades ago.

The enclosure, recorded in the Sites and Monuments Record as LI031-199----, was identified during the Bruff aerial photographic survey of 1986, catalogued as Bruff 100.1, reference AP 4/3598. Enclosures of this kind, broadly speaking, are roughly circular or oval earthworks formed by a bank and ditch, and were used across many centuries of Irish prehistory and early medieval life for settlement, agriculture, or ritual purposes. What brought this one back into documented existence was the survey work compiled by Edmond O'Donovan and uploaded to the record in October 2020. The record also notes two neighbouring enclosures in the same area: one lying approximately 125 metres to the east, and a second about 110 metres to the northwest, suggesting this part of Glenogra was once a more populated or organised landscape than the unremarkable pasture visible today.

Because the site is not visible on any current satellite or aerial imagery, there is nothing obvious to look for from a distance. The enclosure sits on flat agricultural land near the Coolfune townland boundary, which means the ground itself gives little away to the casual observer. The best approach, for anyone with a scholarly interest rather than a walking one, is through the National Monuments Service record, where the Bruff survey image provides the clearest picture of what was once detectable here. The fact that two related enclosures survive nearby suggests the broader field system may reward further investigation, though whether any of these sites retain visible surface traces is a question the current record leaves open.