During archaeological monitoring ahead of the bypass work, excavators uncovered a low, oval mound of heat-shattered stones and charcoal-darkened soil at Curraheen, measuring roughly 3.8 metres by 2.8 metres and only about 10 centimetres deep. What made the find more arresting than a single roadside anomaly was the company it kept: this mound was one of six similar features clustered in the same area, with the nearest neighbours sitting roughly 30 metres to the north-east and east respectively.

The features belong to a class of monument known in Irish as fulachtaí fia, the singular being fulacht fia. These are among the most commonly recorded prehistoric sites in Ireland, typically consisting of a horseshoe-shaped or irregular mound of fire-cracked stones accumulated beside a pit or wooden trough. The working theory, broadly accepted though still debated, is that stones were heated in a fire and dropped into the water-filled trough to bring it to a boil, most likely for cooking, though uses ranging from textile processing to bathing have been proposed. Partial excavation at Curraheen in 2002 did not expose any pit or trough within the area that was investigated, which may simply reflect the limits of what could be dug within the road corridor; the mound itself extended southward beyond the boundary of the road-take, suggesting more of the site remained undisturbed beneath the surrounding ground.

The clustering of six such monuments in one relatively small area is the detail that lingers. Whether they represent repeated activity over generations at a particularly favoured spot, or something more organised about the use of this landscape, the ground at Curraheen clearly held significance for the people who worked it, long before a bypass was ever drawn on a map.