That is the quietly odd circumstance at the heart of this site near Croom in County Limerick. Ringforts, sometimes called raths, were enclosed farmsteads of the early medieval period, typically defined by one or more earthen banks and ditches, and they are among the most common archaeological monument types in Ireland. What makes this one unusual is not its form but its invisibility: it simply was not there, cartographically speaking, until the road engineers arrived.

Celie O'Rahilly, the Limerick County Archaeologist, identified the levelled enclosure in advance of construction of the Croom Bypass, and archaeological testing followed under licence in 1997, carried out by Thaddeus Breen. Geophysical survey revealed a circular ditch with a break on one side, most likely the original entrance, and evidence of a second adjoining enclosure to the north. Five post-holes were uncovered in the centre of the enclosed area, the kind of pattern that can indicate a roofed structure, though no finds of note came from the excavation itself. Further monitoring in 1999 by Martin Fitzpatrick established that the site was a subcircular raised area measuring roughly 27.4 metres north to south by 25 metres, sitting about half a metre above the surrounding ground. Both this monument and the adjoining ringfort to the north had been levelled during the nineteenth century, almost certainly as part of the intensive field drainage operations that left stone-filled drains threaded throughout the area. The eastern portion of the site, which fell within the road corridor, was investigated; the remaining two-thirds were left undisturbed.

The bypass now clips the eastern edge of where the monument once stood, and much of what survives lies in ordinary pasture beside the road, 115 metres west of the Maigue and on the townland boundary with Tooreen. There is no formal access or signage. The clearest view of what remains is not from the ground at all but from above: a faint semi-circular cropmark is visible on satellite imagery, most legibly on an orthoimage taken in March 2017. For anyone curious enough to look it up on Google Earth before visiting, that pale arc in the grass is about as much as the site now offers to the eye, which is, in its own way, a reasonable summary of what nineteenth-century drainage and twentieth-century road-building together managed to leave behind.