A rath, the Irish term for a ringfort, was typically a defended farmstead enclosed by one or more earthen banks and ditches, home to a farming family of some social standing during the first millennium AD. This one at Ballinlag measures roughly 28 metres across, and though the centuries have softened its profile considerably, enough survives to read its original shape.

The enclosure is defined by a scarp, a steep earthen face, that still stands 1.55 metres high at its north-northwest arc and 1.3 metres at the southwest. A short remnant of stony bank clings on at the south, and loose stones tumble down the outer slope in places where the structure has begun to unravel. A gap of about two metres at the east-northeast, partly obscured by fallen stone, may mark the original entrance, though the southeast arc has either eroded away or been deliberately levelled, leaving a broader opening there. Just outside the western edge, cattle have worn a shallow trackway into the ground, following what might once have been a fosse, the external ditch that would have reinforced the enclosure. Whether any original ditch survives beneath that depression, however, remains genuinely uncertain. The ridge position is telling: a fall of ground to the southwest and west overlooks a stream valley roughly 200 metres away, the kind of placement that gave early farmers both drainage and a decent line of sight across their land.

The interior has not been entirely left alone. A later field wall bisects the western half of the rath, now swallowed up in hawthorn and brambles, and a large pit, ten metres by seven and 1.6 metres deep, has been cut into the southern half. Whether that pit is the result of deliberate digging, subsidence, or some older disturbance is unclear, but it has broken the integrity of the interior considerably. Blackthorn scrub has colonised most of the monument, and rabbit burrows riddle the earthwork, which is a reminder that the slow, unglamorous work of erosion rarely stops.