Measuring roughly four metres across and less than a metre high at its tallest point, it is modest enough that a driver might pass without a second glance. What makes it quietly interesting is precisely the uncertainty surrounding it: the form and position of the cairn suggest it may not be an ancient monument at all.

Local tradition, recorded by Ó Cíobháin in 1985, identifies the mound as a leacht cuimhne, a term for a memorial cairn, typically a modest heap of stones accumulated over time as passers-by each add a stone in remembrance of someone who died at or near the spot. The practice is an old one in Ireland, rooted in the idea that each stone laid continues the act of commemoration, keeping the memory of the deceased alive through repeated, anonymous gesture. Unlike the megalithic cairns of prehistory, which were built as deliberate, engineered structures, a leacht cuimhne grows organically, and its irregular, pebble-heavy composition at Derrynablaha is consistent with exactly that kind of gradual accumulation. Who is remembered here is not recorded, but the gap itself, exposed and windswept, is the kind of place where accidents and hardships would have been common enough across the centuries.