What was once a circular earthwork enclosure, with a small square building at its centre, now survives only as a faint clayey band in the soil, a difference in grass growth that hints at the backfilled fosse, the defensive ditch that originally defined the enclosure's outer edge.

A ringfort is an enclosed farmstead, typically of early medieval date, formed by one or more banks and ditches surrounding a domestic or agricultural space. The example at Calliaghstown appeared on the 1837 Ordnance Survey Fair Plan map as a circular enclosure with a smaller circular feature at its centre, possibly a house site. By 1966, when an Office of Public Works field officer visited, the monument was still upstanding enough to be measured and described: an enclosure roughly 43 paces across on the northwest to southeast axis, its lower southwestern end built up with small field stones to create a level platform on the gently sloping hillside. Within that levelled space sat the foundations of a small square building, approximately nine to ten paces on each side. The officer noted it looked rather like an old farmyard. Sometime between that 1966 visit and 1970, the whole thing was levelled. A second ringfort lies around 80 metres to the southeast, suggesting the area was once a more populated landscape than the open pasture now implies. Fragments of charcoal and bone visible in the disturbed soil are all that remain of whatever domestic life once took place inside those walls.