These sites, dating broadly to the Bronze Age, are typically identified by a horseshoe-shaped mound of fire-cracked stone and charcoal-blackened earth, the accumulated debris of a process in which stones were heated in fire and dropped into a water-filled trough to bring it to the boil. Thousands of them survive across the island, often close to streams or boggy ground, and yet the precise purpose of so many of them remains genuinely debated. Cooking, brewing, textile processing, and communal bathing have all been proposed with varying degrees of archaeological support.

The site at Aglish sits within a county that contains a considerable concentration of prehistoric monuments, scattered across a landscape that has been farmed and modified for millennia. Fulachtaí fia, as they are known in the plural, are frequently discovered by chance, during drainage work or field levelling, which means their survival at all is often a matter of luck rather than deliberate preservation. The mound form that distinguishes them in the field is essentially the waste heap of repeated use, built up over what may have been generations of activity in the same spot.