The rath at Killeenboy in County Westmeath sits on a small rise in undulating pasture, commanding views in every direction, the kind of elevated position that Early Medieval farming families chose deliberately when they threw up these circular earthen enclosures as farmsteads and family compounds. What remains today is considerably less than what was once there, and the story of its disappearance is mapped with some precision across two Ordnance Survey editions.

The 1837 six-inch OS map recorded a roughly circular enclosure sitting about twenty metres south of a public road. By the time the revised twenty-five-inch edition was drawn up in 1913, the same feature had been reduced to a horseshoe shape, the gap in the circle indicating that quarrying had eaten into the monument somewhere in the intervening decades. When the site was described in 1980, the picture was bleaker still. The oval interior, measuring roughly 21 metres east to west and 16.5 metres north to south, was defined only by a low scarp, the kind of slight change in ground level that is all that survives when an earthen bank has been substantially removed. The original entrance was no longer identifiable, and there was no surviving external fosse, the defensive ditch that typically encircles a rath of this kind. Most of the interior had been quarried away, leaving a shallow depression filled with small field clearance stones, the agricultural detritus of later generations. Livestock had disturbed the perimeter further, and vegetation had moved in across much of what remained. A preservation order was placed on the monument in November 1983, by which point the damage was already extensive.

What can be seen now, visible on aerial photography, is a roughly circular tree-planted enclosure, the vegetation that once marked the monument's decline having become, in a sense, its most legible feature. The trees trace the outline of something that the ground itself can no longer clearly articulate.