It measures twenty-one metres long, fourteen metres wide, and barely sixty centimetres high, and to most eyes it would read as little more than a slight rise in the ground. But the material beneath that grassy skin is burnt and fire-cracked stone, the characteristic signature of a fulacht fia, and it has been accumulating there since prehistory.

Fulachtaí fia are among the most common archaeological monuments in Ireland, yet they remain genuinely mysterious. The name translates roughly as "deer roast" or "wild deer cooking place", and for much of the twentieth century they were interpreted as outdoor cooking sites, where large wooden troughs were filled with water and heated by dropping fire-cracked stones into them. More recent thinking has broadened that picture considerably, with proposals ranging from textile processing to brewing, though no single explanation has settled the debate. What is consistent across sites is the association with water and the telltale horseshoe-shaped mound of discarded, shattered stone that builds up over repeated use. At Gort An Imill, the mound has two distinct openings, one facing south-west at three metres wide and a second facing east-south-east at two metres, suggesting the trough or working area was approached from more than one direction, though the precise arrangement of any original timber feature is no longer visible at the surface.