Modern field boundaries now trace part of its circuit, one of them possibly built directly on top of the original bank, so that the ancient and the agricultural have become difficult to separate. What survives is a roughly circular area about 38 metres across, defined on one side by an overgrown earthen bank still standing close to two metres high, and on the other sides by a combination of later stonework, recent hedging, and the faint ghost of a low bank that has almost returned to the ground.

A rath is an early medieval farmstead enclosure, typically dating from roughly the sixth to the twelfth century, in which an earthen bank and ditch enclosed a household and its outbuildings. Thousands survive across Ireland in various states of preservation, and this one in Rath Beg was already old enough to be mapped by the time the Ordnance Survey produced its six-inch sheets in 1846, recorded there as a circular enclosed area of around 35 metres in diameter. More intriguing is a piece of local memory preserved through the Irish Schools Manuscript scheme of the 1940s, a nationwide project in which schoolchildren collected folklore and local knowledge from older community members. That record, associated with land then belonging to a David P. O'Sullivan, noted the presence of a few grave-like mounds of earth within the enclosure. Whether those mounds represented burials, structural remains, or something else entirely was not established, and they do not appear to have been investigated further.