Around 1920, residents witnessed the destruction of what they described as 'a sort of dolmen'; a large coffin-shaped stone that once rested on three upright supports. This ancient structure had likely stood for millennia before meeting its unfortunate end, joining the countless prehistoric monuments lost to agricultural expansion and stone quarrying across Ireland during the early 20th century.

Today, visitors to the site will find only tantalising hints of what once stood here. A substantial pillar-like stone, measuring 2.2 metres in length, 0.4 metres wide and 0.2 metres thick, lies fallen on a boggy ridge. Beside it stands a low upright stone that may represent the broken base of the toppled pillar, suggesting this could have been a standing stone rather than part of the reported dolmen. The exact relationship between these remains and the destroyed monument remains uncertain, though local knowledge passed down through generations insists this lonely spot once hosted something far more impressive.

The site was officially recorded in the Survey of the Megalithic Tombs of Ireland in 2002, though its classification remains uncertain. Whether it was truly a dolmen, a portal tomb typical of the region, or perhaps a standing stone marking an ancient boundary or burial site, we may never know. What remains clear is that Ballagh's mysterious monument joins a long list of Ireland's prehistoric heritage that exists now only in memory and fragmentary field evidence; a reminder of how much archaeological knowledge has been lost to time and human activity.