Where most of these early medieval enclosures survive as open earthworks in farmland, the rath at Killygorman in County Monaghan has been swallowed by a deciduous wood, its circular form now legible only to those who know what to look for beneath the canopy. Ringforts, or raths, were typically the enclosed farmsteads of early medieval Ireland, their banks and ditches defining a domestic space rather than a military one, and this example preserves enough of its original structure to give a clear sense of its former shape.

The site sits on the western shoulder of a drumlin ridge running roughly east-north-east to west-south-west, the kind of glacially deposited landform that gives County Monaghan its famously lumpy terrain. Drumlins are elongated hills of compacted glacial till, laid down during the last ice age, and they offered early settlers elevated, well-drained ground with good sightlines. The enclosure itself is roughly circular, measuring approximately 26.5 metres east to west and 25 metres north to south. On the western side, a scarp, essentially a steep earthen face, rises to about 2.4 metres, making this the most visibly dramatic element of the site. Around the south-west, faint traces survive of an outer fosse or berm, a shallow external ditch or bank roughly three metres wide, and on the north-east there is a section of outer stone wall facing standing to around 1.8 metres. The combination of an earthen scarp and a stone-faced outer wall is not unusual in Monaghan, where builders worked with whatever the local landscape offered, but together they hint at an enclosure that was carefully constructed rather than casually thrown up. No original entrance has been identified.