What makes it unusual is not just its size, roughly eighteen metres across in both directions, but the layered identity it carries: Bronze Age cooking site, post-medieval industrial structure, and now an irregular, vegetation-smothered lump in pasture that gives little away at first glance.

A fulacht fia, sometimes written fulacht fiadh, is a type of prehistoric cooking or processing site found in enormous numbers across Ireland. The classic form involves a trough filled with water, heated by dropping fire-cracked stones into it, with the discarded burnt stone accumulating into a horseshoe-shaped mound over repeated use. The mound at Aughrim contains exactly this kind of burnt material, visible at its northern end. At some later point, probably in the post-medieval period, someone made use of what was already a substantial earthwork and built a lime kiln into or around it. A lime kiln was a simple but important piece of rural infrastructure, used to burn limestone to produce quicklime for agricultural or building purposes, and they were often constructed against or into existing earthen banks for structural support. The result here was a blurring of the original archaeology beneath layers of later activity. By 1842, when the first detailed Ordnance Survey mapping was carried out, the site was recorded simply as a lime kiln, its prehistoric origins unrecognised. Later surveys in 1905 and 1937 described it instead as a circular mound, suggesting the lime kiln had by then fallen into ruin and the feature had been reassessed, if not fully understood. A slightly raised linear feature to the south-west of the mound may represent what remains of a loading ramp associated with the kiln.

The mound sits in pasture and is described as heavily overgrown, which is worth bearing in mind if you are trying to read the topography. The irregular shape and uneven height that result from the layered history of the site mean it does not present the clean horseshoe profile that many fulachtaí fia display elsewhere.