This one barely announces itself at all. In the low-lying wet pastures of Moohane in County Limerick, a prehistoric barrow exists primarily as a ghost, visible only under the right conditions from the air, and then only sometimes. It is classified as a cropmark, which means the buried remains beneath the soil subtly affect how the grass and crops above them grow, producing a faint but legible outline when seen from altitude. The circle it traces is there in principle; finding it in practice is another matter entirely.

The site was first identified by Grogan in 1989, who recorded it at page 243 of his survey as a circular-shaped cropmark and assigned it the label Moohane 3. The surrounding landscape offers some context for why something prehistoric might be here at all. Two further enclosures lie relatively close by, one roughly 27 metres to the north-west and another about 190 metres to the south-west, suggesting this part of Moohane was once a more actively used stretch of ground than it appears today. The Camoge River runs approximately 105 metres to the east, where it also marks the townland boundary with Herbertstown. That kind of boundary function often preserves older land divisions, and rivers have long served as natural markers separating one community's territory from another. The site itself does not appear on any Ordnance Survey Ireland historic maps, which places its formal recognition firmly in the modern era of aerial and remote-sensing archaeology.

What makes this site particularly elusive is its inconsistency across different imaging surveys. Orthoimages taken by Ordnance Survey Ireland between 2005 and 2012 show the semi-circular cropmark clearly enough to record. Images taken by Digital Globe between 2011 and 2013 show nothing, and a Google Earth image from June 2018 shows nothing either. Cropmarks of this kind depend on specific combinations of dry weather, crop stress, and the right angle of light, so their visibility can shift dramatically from one season or year to the next. For anyone curious enough to visit the general area, the land is wet pasture crossed by drains and watercourses, and access will depend heavily on ground conditions. The barrow itself, whatever physical remains survive beneath the surface, gives no outward sign of its presence to someone standing in the field.