It is a fulacht fia, a type of Bronze Age cooking site found in great numbers across Ireland, typically identified by its characteristic crescent or horseshoe profile and its contents: heat-shattered stones and charcoal-darkened soil, the debris of repeated heating and water-boiling over many centuries. This particular example measures roughly 5.7 metres east to west and 5.1 metres north to south, rising only about 0.6 metres above the surrounding ground, with its opening, just under two metres wide, facing east.

Erosion on the eastern side of the mound has already begun to expose what lies within, bringing fragments of fire-cracked stone and charcoal-rich soil to the surface. This kind of gradual unravelling is common at fulachtaí fia, since the mounds are essentially middens of discarded material, built up over time as hot stones were cracked by repeated heating and dumped to one side. The process of use was straightforward: stones were heated in a fire, then dropped into a water-filled trough to bring it to a boil, and the spent, fractured stones were piled nearby. What makes the Ardgroom Outward site quietly notable is that it does not stand alone. A second burnt mound lies approximately 120 metres to the west, suggesting that this particular stretch of streamside ground was a focus of repeated, perhaps seasonal, activity during prehistory.