A ringfort, or rath, typically consisted of a bank and ditch surrounding a family's dwelling and outbuildings, offering a degree of security and a visible marker of status in the landscape. This one at Cloonbannin survives as a gentle swell in the ground, its exterior height no more than 0.3 metres, tracing an arc from north-north-east round to west before disappearing entirely.

The reason it disappears is recorded on the Ordnance Survey six-inch map of 1842, which shows the enclosure as a hachured circle with a diameter of around 20 metres. By that point, or sometime close to it, a field boundary running north-east to south-west had already been driven through the site, cutting off the north-western portion. Today that north-western arc leaves no surface trace at all; the bank has been absorbed into the field system, leaving only the surviving south-eastern curve to suggest what was once a complete enclosure. The current measured diameter, taken from the visible remains, comes in at 24.9 metres, slightly larger than the earlier cartographic estimate, which is a common enough discrepancy when comparing map depictions with ground survey.