Look at the first Ordnance Survey map of 1839 and it appears as a large sub-square enclosure, its sides predominantly straight, with a road running along the northeast edge and field boundaries pressing in on the others. Return to the revised map of 1900 and the geometry has quietly shifted: the southeast and southwest sides are now drawn as straight, while the northeast and northwest sides curve. The monument has not moved, of course. What changes between the two surveys is the cartographer's interpretation, and that slippage hints at how difficult the site is to read, even from above.

On the ground, the enclosure measures roughly 75 metres northwest to southeast and up to 60 metres northeast to southwest, tapering noticeably toward the southeast end, where it narrows to about 33 metres. The historian William Carrigan, writing in 1905 in his history of the diocese of Ossory, called it "a fine circular fort called Rathcusack", a name that carries the Irish "rath", meaning a roughly circular earthen ringfort of the early medieval period, the kind once used as a defended farmstead by a family of some local standing. The name Rathcusack presumably preserves an older territorial or personal association now otherwise lost. Whether Carrigan's confident identification of it as circular reflects what was visible at the turn of the twentieth century, or simply a conventional assumption about such monuments, is hard to say; the cartographic evidence suggests the shape was already ambiguous by then.

The site today is heavily overgrown with scrub, which makes reading the earthwork in person a matter of patience rather than clear revelation. The boundaries of the enclosure survive partly as field margins, meaning the monument has been absorbed into the working landscape over generations rather than preserved apart from it.