What was once a rath, a type of circular earthwork enclosure used as a farmstead during early medieval Ireland, has been levelled to the point where only a slight rise in the pasture hints at what lies beneath. Above ground, the eye finds little. From the air, though, the story reasserts itself: aerial photography has captured a cropmark, a dark band tracing a near-perfect circle across the field, formed where the buried remains of the bank affect the moisture and growth of the grass above.

The enclosure was recorded on Ordnance Survey six-inch maps in 1842, 1904, and again in 1939, each time shown as a hachured circle of roughly 35 metres across. Hartnett, writing in 1939, described a single rampart with no trace of an outer fosse, the ditch that typically accompanied such banks as an additional line of defence or demarcation. He noted a possible entrance to the east, along with three other breaks in the bank, and gave the overall diameter as 136 feet. That a researcher was still able to observe and describe the earthwork's structure in 1939 suggests the levelling came later, most likely as agricultural land use intensified in the latter half of the twentieth century, a fate that has claimed a significant proportion of Ireland's estimated 50,000 or more ringforts.

What remains of Ballykerwick today is largely invisible to the casual eye, buried beneath working pasture. The cropmark evidence suggests the circular form is still legible underground, which means the site endures in a sense, just not in a way that rewards a casual visit. Its interest lies less in what can be walked around and touched than in what it illustrates about how thoroughly a landscape can absorb its own past.