Fulachtaí fia, as these sites are known in Irish, are among the most common archaeological monument types in Ireland, yet they remain poorly understood in terms of their precise function. The typical interpretation is that they represent the remains of ancient burnt mound sites, where stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil. The crescent or horseshoe-shaped mounds that survive are composed of the discarded, heat-shattered stone, accumulated over repeated use. The one at Gortnascreeny measured roughly 22 metres in length and 10 metres across, with a possible opening or hollow to the western side that may once have indicated the position of the trough or working area.

The site had the characteristic feature shared by nearly all fulachtaí fia: a ready water source close at hand. Both a stream and springs lay nearby, which would have made the location practical for whatever activity was being carried out here, whether cooking, bathing, or some form of craft work such as hide preparation. Unfortunately, the mound was levelled around 1978, removing whatever physical presence it once had in the field. What had survived for perhaps three thousand years or more was gone within a single season of agricultural work, a fate that has befallen a great many similar monuments across the country.