The fort at Tassan in County Monaghan did not get that chance. By the time anyone thought seriously about what it might mean, it was already gone, buried under farm buildings sometime after 2012.

When it was recorded in 1968, the site presented as a roughly circular, grass-covered enclosure, measuring approximately 43.4 metres across its north-east to south-west axis and around 40 metres the other way. A low earthen bank defined its perimeter, standing no more than 0.7 metres above the exterior ground level on the western side, with a base width of just over three metres. There was no visible fosse, which is the external ditch that typically accompanies an earthen ringfort and helps to date and classify it. Instead, an outer field bank ran around much of the circuit from west through north to south-south-west, blurring the boundary between ancient monument and working farmland. The interior held rock outcrops and quarry mounds, and wide gaps in the bank on the south-south-east and west-north-west sides had long been in use by farm machinery. Archaeological testing carried out in 2007 to the south-east of the monument, reported by Russell in 2008, produced no related material, leaving the site's origins and date unresolved. It sat on a gentle south-east-facing slope, unremarkable to a passing eye, already half absorbed into the agricultural landscape around it before it disappeared entirely.