It sits in a landscape dotted with hollows, surrounded by grassed-over mounds that may or may not be the same kind of thing, and nobody is entirely sure whether any of it is man-made at all.

The site was noted on the third edition of the Ordnance Survey six-inch map, published in 1932, where it was recorded as a small mound of around fifteen metres in diameter. A later inspection found the feature to be somewhat larger, a slightly raised circular area of twenty-five metres, set among what the Office of Public Works topographical files described as possible natural hummocks or eskers. An esker is a long, winding ridge of gravel and sand deposited by meltwater streams running beneath a glacier, and they are relatively common across the Irish midlands and west; the honest difficulty at Carrowculleen is that such natural formations can look, at ground level, very much like deliberate earthworks. The low, flat, waterlogged terrain makes it harder still to distinguish one from the other.

What lingers about this place is precisely that uncertainty. It was recorded as an earthwork, catalogued and mapped, and yet the evidence on the ground stops short of confirming any human intention. The mounds remain grassed over, unexcavated, sitting in their marshy field beside the stream, neither confirmed as ancient monuments nor dismissed as mere geology.