It measures just over seventeen metres long and thirteen wide, rising less than a metre above the surrounding soil, with an opening of about four and a half metres facing north-east. To most passers-by it would look like a slight rise in a damp field. To an archaeologist it is immediately recognisable as a fulacht fia, one of the most common yet persistently puzzling monument types in the Irish landscape.

Fulachtaí fia, found in their thousands across Ireland, are Bronze Age cooking sites, typically dating from around 1500 to 500 BC, though some may be earlier or later. The standard interpretation is that stones were heated in a fire, then dropped into a water-filled trough to bring it to the boil, cooking meat wrapped in straw or hides. The process shattered the stones, and over repeated use the broken, fire-cracked fragments accumulated into the characteristic horseshoe-shaped mound that survives today. The shape at Coolaniddane is a good example of this form, its opening oriented north-eastward and a well recorded at its south-eastern side, presumably a water source that fed the trough. The boggy, streamside ground is entirely typical; these sites almost always cluster near water and low-lying wet terrain. What makes this particular location quietly notable is the proximity of a second fulacht fia roughly forty metres to the west, suggesting the area saw repeated or sustained use across the Bronze Age, or perhaps use by different groups at different times.