A local antiquarian named Windele, who had visited some years earlier and recorded what he saw as "an old kile, which formed an oblong square, 16 to 20 paces broad, and somewhat longer", returned to find the earthwork gone and the land under cultivation. It is a peculiarly complete disappearance, and yet the site refuses to be entirely forgotten. A faint circular rise, roughly 18.5 metres across, can still be traced running from west to southeast across the pasture, the last trace of what the 1842 Ordnance Survey map had confidently named "Kilcullin fort" and drawn as a hachured enclosure of around 30 metres in diameter. By the editions of 1904 and 1938, the cartographers had downgraded it to "Kilcullin fort (site of)", a bracketed qualification that speaks volumes.

The site carries several layers of strangeness. Its name, glossed in an 1839 Ordnance Survey field description as "church of the holly", points to an early Christian presence, and the fort itself sits within the north-eastern half of what appears to have been an early ecclesiastical enclosure. That same field description noted that the fort "is considered was on a burying ground, on account of a good number of human bones having been got in it", suggesting that whatever stood here was already associated with the dead before it disappeared from the landscape entirely. A ringfort, to give it its more familiar name, is a type of enclosed farmstead common across early medieval Ireland, typically defined by one or more earthen banks and ditches. That this one was nested inside a religious enclosure, and sat above human remains, places it at an unusual intersection of the secular and sacred. A standing stone survives on the north-western perimeter of the site, and a souterrain, an underground stone-lined passage of the early medieval period, was discovered roughly 28.5 metres to the north-west, hinting at a more complex arrangement of features than the ploughed-out ringfort alone would suggest.