It runs straight through the middle of an ancient ringfort, bisecting it on an east-north-east to west-south-west axis along a modern field wall. That administrative line, drawn long after anyone stopped building ringforts, now cuts across a site that was clearly conceived as a unified whole, a double-ringed enclosure sitting on a low natural rise in open grassland, with good views in most directions and a hillfort visible on the north-eastern horizon.

Ringforts, also called raths, were the most common form of enclosed settlement in early medieval Ireland, typically consisting of a raised circular area defended by one or more earthen banks and ditches. The Ballyheeragh example is more elaborate than most. A slightly raised central platform, roughly 26 or 27 metres across, is separated from an outer enclosing bank by a broad terrace or annular gap several metres wide, giving the whole structure a diameter of around 45 metres. The banks survive unevenly: on the northern half they appear as slumped earthen slopes and low sod-covered stony ridges, while the southern half retains more defined scarps with traces of a stone wall or bank along the top. Complicating matters considerably, additional low walls radiate outward from the inner ring across the terrace on the southern side. These may not be original features. A rectangular building, probably a late nineteenth-century house, is shown abutting the outer north-eastern edge of the ringfort on the 25-inch Ordnance Survey map, though it does not appear on either the 1838 or 1915 six-inch editions, suggesting a relatively brief occupation. A remnant of that structure has since been absorbed into a field wall, and relict cultivation ridges survive in the field immediately to the south-east, quiet evidence of the working landscape that grew up around and eventually over the earlier one.

The site is not easy to read on the ground. Long grass and thistles make the earthworks difficult to trace, and the overlapping layers of field walls, one of them a county boundary, a probable nineteenth-century house, and the underlying early medieval enclosure, demand some patience to disentangle visually. The sheltering hillock to the south and the distant hillfort to the north-east are worth noting as orientation points once you have found the site.