It is a ring-ditch, a type of monument typically consisting of a circular ditch dug into the ground, often surrounding a central burial or pit, and associated in Ireland with prehistoric funerary or ritual use. What makes this particular feature quietly compelling is that it was not found by accident or by the spade of a developer, but by a geophysical survey that detected its presence without a single trench being opened.

The survey was carried out under licence number 12R010 by the Discovery Programme, the Irish state-funded body dedicated to large-scale archaeological research, as part of its project investigating Late Iron Age and so-called "Roman" Ireland, a period when Irish society was developing in complex ways while simultaneously maintaining contact, however indirect, with the Roman world across the water. The survey identified archaeological activity concentrated towards the summit of the hill, and within that activity, a ring-ditch measuring fifteen metres in diameter, enclosing a central pit. The monument was not found entirely intact. Along its northern edge, quarry activity had cut into the feature, removing part of the ditch circuit and leaving the rest to survive beneath the surface undisturbed. This damage was recorded by Dowling in 2013.

Because the ring-ditch was identified through geophysical rather than excavation survey, there is nothing to see at ground level in any conventional sense. A visitor to the Popeshall hilltop would find themselves standing on farmland with no visible earthwork or marker to indicate what lies below. The value of the site is perhaps more conceptual than visual: the knowledge that the hilltop was chosen, in prehistory, as a place of some significance, and that even partial destruction by later quarrying has not entirely erased what was put there. Anyone with a serious interest in the project's broader findings would do well to consult Dowling's 2013 report, which places this feature within a wider regional survey.