What makes this one on Grange Hill in County Limerick stranger still is that it once contained a hoard of prehistoric axes, that one of those axes spent decades as a family heirloom on the farm above it, and that the cave itself was at some point misidentified on paper as a fort. The entrance, clearly marked on the Ordnance Survey six-inch map of 1840, simply does not appear on later editions, and remains invisible on aerial imagery today, swallowed by dense gorse on the north-west-facing slope of the hill.

The cave is a natural single-chambered hollow in a limestone knoll, roughly 5.8 metres deep and wide enough at the mouth to walk into without stooping, though it narrows considerably towards the rear. Porcellanite is a fine-grained volcanic rock quarried in Neolithic Ireland, most famously at Tievebulliagh in County Antrim, and the presence of a miniature porcellanite axe here, just 7.6 centimetres long, points to connections stretching well beyond the local landscape. The hoard was discovered in 1917 or 1918, and it was Professor M.J. O'Kelly who recorded the find. One of the two identified axes was deposited with the archaeology department at University College Cork; the other, a larger example at 26.7 centimetres, remained with the landowning family as a heirloom. O'Kelly also noted in 1944 that the cave was permanently waterlogged, a description that did not hold true when the site was examined again in 2003. The entrance appears to have been partly quarried in the late nineteenth or early twentieth century, which may explain both the alteration to its appearance and its disappearance from later maps. A separate monument recorded in the archaeological inventory as an enclosure turned out, on closer inspection, to be nothing more than a cartographic representation of the cave entrance on that same 1840 map.

The site sits at around 91 metres above sea level on Grange Hill, roughly 60 metres west of the summit, and the surrounding landscape is well worth paying attention to even if the cave itself proves elusive. A standing stone lies approximately 70 metres to the west, and a genuine enclosure sits 15 metres to the south-east. Lough Gur, one of the most archaeologically significant lake landscapes in Ireland, is only 1.5 kilometres to the south, though it cannot be seen from the cave. Anyone attempting to locate the entrance should expect thick gorse and no clear path; the densely overgrown patch visible on satellite imagery is the most reliable indicator of where to look. The westward-facing mouth, when found, offers open views across the surrounding countryside.