The ground above it is flat and ordinary, giving no hint that anything lies beneath. Yet as recently as 1943, an Ordnance Survey map recorded a visible mound on the spot, which means that within living memory there was still something to see. Whatever remained above ground has since been absorbed into the agricultural landscape, levelled out in the process of land improvement.

The site is a fulacht fia, a type of ancient burnt mound found in enormous numbers across Ireland, typically dating to the Bronze Age. The term, sometimes translated loosely as "cooking place of the deer", refers to the characteristic horseshoe-shaped mounds that form when fire-cracked stone is repeatedly discarded after use. The standard interpretation is that stones were heated in a fire, then dropped into a water-filled trough to bring the water to boiling point, a method used for cooking meat. Some researchers have also proposed uses ranging from textile processing to bathing. The mounds themselves are essentially middens of shattered, heat-fractured stone, which is why they survive at all, the material being of no particular agricultural use until modern land-reclamation techniques made even low mounds an inconvenience. At Garranenamuddagh, that threshold was apparently crossed sometime between 1943 and the present, and the surface trace has gone entirely.