The name, loosely translated from Irish, refers to a type of monument found in enormous numbers across Ireland, more than five thousand recorded to date, yet each one easy to overlook. They typically survive as horseshoe-shaped or kidney-shaped mounds of fire-cracked stone, built up over generations of use around a trough, usually timber-lined or cut into the ground, into which water was poured and heated by dropping in stones fired in an adjacent hearth. The stones eventually shatter from repeated thermal shock and are discarded into the mound, which is how they accumulate. It is a deceptively simple technology, and it worked.

The fulacht fia at Ballinlough belongs to a class of monument that flourished mainly during the second millennium BC, though some sites show evidence of use stretching into the Iron Age. They cluster near water, since a reliable source was essential to the whole process, and this one in Kilkenny is no exception to the broader pattern. Beyond its location in Ballinlough, the specific details of this particular site, its dimensions, its condition, any associated finds, remain unavailable at present. What can be said is that its survival into the modern record at all is quietly remarkable. These sites were once dismissed as the debris of ancient deer hunts, hence the folklore name, but archaeological thinking now considers cooking, food preparation, and possibly other uses involving hot water, whether for textile processing or bathing, as far more plausible explanations. The debate has not fully settled.