A rath, as this type of monument is commonly called, is an early medieval enclosed farmstead, typically defined by a circular earthen bank and an outer ditch known as a fosse, within which a family and their livestock would have lived. At Ballynacarrow, even those defining features are gone, and what remains is little more than a ghostly circular cropmark, visible only from the air on aerial photography, where differential growth in the vegetation betrays the buried outline of a structure some 35 metres across.

The site has a quietly melancholy paper trail. When the first Ordnance Survey six-inch map was produced in 1837, the earthwork was clear enough to be annotated as a fort, with a bank, fosse, and even a small circular hut site recorded within the interior. By the time the revised twenty-five-inch map was compiled in 1913, the outline had shifted slightly to a rougher oval shape, suggesting the earthwork was already being encroached upon. A field inspection in September 1967 found it reduced to a vegetable garden with a barely perceptible bank no more than a foot high, the inspector noting only a small sub-rectangular patch of uncultivated ground as evidence of something older beneath. Four years later, in 1971, it was recorded as completely levelled, with no surface remains visible whatsoever. What had been a legible monument on a mid-nineteenth-century map had, within little more than a century, been absorbed entirely into the working landscape around it.

The site today offers nothing to the casual eye at ground level. The clearest evidence of its existence comes not from walking the field but from looking down at it, where a heavier growth of vegetation still traces the perimeter in a roughly circular form, and the cropmark pattern remains detectable in aerial imagery. It is a reminder that many of Ireland's thousands of ringforts survive not as upstanding earthworks but as faint impressions in soil and crop, readable only when conditions and the right vantage point align.