It sits in rough grazing land, about thirty-five metres north of a stream, looking to the casual eye like little more than an overgrown hump in a field. That ordinariness is, in a sense, the point.

A fulacht fia is a burnt mound, the accumulated debris of repeated episodes of stone boiling. The basic process involved heating stones in a fire, dropping them into a water-filled trough to bring it to temperature, and then discarding the cracked, spent stones into a heap nearby. Over many uses, that heap grew into a low, horseshoe-shaped or circular mound, typically dark with charred and shattered material. The Doonasleen example is roughly circular, about twelve metres across and just under a metre high, and may have a central depression where the trough once sat, though the vegetation has made that difficult to confirm. Most fulachta fia date to the Bronze Age, broadly between 2000 and 500 BC, and their proximity to water sources, as here with the nearby stream, is one of their most consistent features. What exactly they were used for remains a subject of genuine debate among archaeologists: cooking and food processing are the traditional explanations, but brewing, hide preparation, and bathing have all been proposed with some seriousness.