It sits on the north-western slope of a low ridge, surrounded by pasture, and at ground level there is simply nothing there to notice. No walls, no obvious earthworks, no trace of a threshold. Whatever drew a cartographer to mark it on the first Ordnance Survey six-inch map in 1837, labelling it plainly as "Fort", has since subsided into the land around it.

A field inspection carried out in 1987 found what the grass conceals: a slightly raised circular area roughly 45 metres in diameter, defined by a wide, low bank of earth and stone, with a shallow external fosse running around its outer edge. A fosse is simply a ditch, typically dug to reinforce a bank or enclosure, and the combination here is consistent with a ringfort, a class of monument built across Ireland from roughly the early medieval period, used as a defended farmstead or high-status residence. The bank and fosse at Derryart are both described as wide and low, suggesting that centuries of agricultural use, weathering, and soil movement have reduced what was once a more substantial structure. The original entrance could not be identified at all.

What makes the Derryart site quietly interesting is less what it contains than what it represents: a place that survived on paper long after it ceased to survive in any legible physical form. The 1837 mapmakers recorded something their successors could barely measure, and that record is now the clearest evidence the site exists at all.