Ringforts, roughly circular enclosed settlements typically dating from the early medieval period, were once among the most common monument types in Ireland, numbering in their tens of thousands. The one at Farrancallin has not fared well. By 1975 it could be described only as a shallow circular raised area, roughly 27 to 35 metres across, sloping gently to the south-west. By November 2011, aerial photography could detect nothing at all.

The site sits on a south-east facing slope of a low rise in open grassland, with wet ground to the south, a setting typical of early Irish settlement where elevated, well-drained ground was preferred. It appears clearly on the first edition Ordnance Survey six-inch map of 1837, drawn as a circular enclosure, but it drops off all subsequent OS editions, suggesting that whatever earthwork remained was already being eroded or levelled during the nineteenth century. The road that now clips the north-east perimeter of the former enclosure also serves as the townland boundary between Farrancallin and Taghmon, a reminder that these ancient features were sometimes absorbed into the administrative and physical fabric of the countryside even as the monuments themselves disappeared. The gentle kink in the road is, in that sense, a kind of fossil, preserving the outline of something that the fields themselves no longer show.