A cashel is a stone ringfort, typically early medieval in date, built from drystone walling rather than earthen banks, and the one at Cartron was already in poor shape when archaeologists first recorded it in April 1992. Even then, what remained of its roughly circular wall, about 28 metres across, had partially collapsed, and a later field boundary had been laid directly over it, running from the south-east, around the western arc, to the north-east. On the southern and western sides, traces of both the inner and outer wall-facing were still legible to a trained eye.

By the time of a follow-up visit in October 2001, thorn and briar had begun colonising the interior, particularly on the eastern side. That growth, left unchecked, would have been damaging enough. Then in 2008 a large outbuilding was constructed in the centre of the cashel. The groundworks required to put it there involved cutting the interior back to boulder clay and removing the cashel wall across the entire northern, eastern, and southern arc. What had been a compromised but still traceable monument became, in the course of a single building project, something considerably harder to read on the ground. The western portion, already overlain by the field wall, is the section most likely to retain any visible trace of the original structure.