That oversight, it turned out, was archaeology's gain. The monument was a ring-ditch, a type of prehistoric enclosure defined by a roughly circular ditch surrounding a raised central platform, often associated with burial or ceremonial activity. This one, sitting roughly 100 metres west of the River Maigue on the townland boundary with Tooreen, measured approximately 24 metres across when first described, and would reveal considerably more complexity once excavation began.

It was Celie O'Rahilly, then Limerick County Archaeologist, who identified the levelled monument ahead of construction works on the Croom Bypass. Archaeological testing followed in 1997 under licence 97E0399, carried out by Thaddeus Breen, who described it as a circular, ditched enclosure with possible associated features beyond the ditch. Full excavation came in 1999, conducted by Fiona Rooney, and the picture that emerged was intricate. The subcircular central area measured 33.3 metres north to south and 31.4 metres east to west, raised about 0.4 metres above the surrounding ground. Much of the ditch had been disturbed by later land reclamation drainage, farmers having, at some point, laid stone drains along the exact line of the ancient cut. In the eastern section, however, a 20-metre stretch had escaped this interference, and here the original U-shaped ditch survived: 2.8 metres wide, about a metre deep, with stone deposits at its north and south terminals containing animal bone, charcoal flecks, and a fragment of a lignite bracelet. Lignite, a soft brownish coal sometimes called jet, was worked during prehistory into decorative objects. A second fragment of the bracelet was recovered from an undisturbed context in the south terminal. Inside the central platform, slot-trenches running east to west suggested the outline of a structure, accompanied by pits, post-holes, and a scatter of cremated bone.

The site no longer exists in any visible form. It was fully excavated ahead of the bypass construction and, as confirmed by aerial imagery taken in June 2018, nothing remains above ground. There is no feature to visit, no earthwork to trace, no marker at the roadside. What endures is the excavation record, held in the archives of the National Monuments Service, and the knowledge that somewhere beneath or beside the modern road surface, later drainage cuts follow the ghost of a ditch that someone, at some unspecified point in prehistory, considered worth the considerable effort of digging.