This oval enclosure, measuring roughly 30 metres northwest to southeast and 26 metres northeast to southwest, was once defined by substantial stone walls about 1.4 metres thick. Today, much of the northern section has vanished entirely, leaving only fragments to hint at its original defensive perimeter. The site occupies an exposed position amongst light pasture and rocky outcrops, typical of the rugged Donegal landscape where such fortifications were built to withstand both weather and potential raiders.

The interior reveals intriguing architectural features that speak to the complex lives of its inhabitants. Two straight walls meeting at right angles divide the northwest quadrant, running from near the centre to meet the outer cashel wall; a later modification perhaps, or evidence of internal divisions for livestock or storage. Most fascinating is an 8-metre gap in the northeastern section, currently bridged by three stone lintels positioned about 40 centimetres above ground level. These may mark the entrance to a souterrain, one of those mysterious underground passages that honeycomb so many Irish ringforts, used variously for storage, refuge, or ritual purposes.

First recorded on the Ordnance Survey 6-inch maps of the 19th century, Cashelnaclogherny represents one of hundreds of similar cashels scattered across Donegal’s windswept hills and coastal margins. These stone-built ringforts served as fortified farmsteads during the early medieval period, housing extended families, their livestock, and stores. The Archaeological Survey of County Donegal, compiled by Brian Lacey and his team in 1983, catalogued this site alongside the county’s other field monuments, preserving crucial details about these remnants of Ireland’s rural past that continue to dot the landscape like ancient punctuation marks in the story of human settlement.