The fort at Drumdartan Glebe is not dramatic in scale, but there is something quietly insistent about its geometry, a near-perfect subcircular outline roughly 28 metres east to west and 25 metres north to south, that refuses to be mistaken for a natural feature.

The site sits on a shelf of east- and south-facing slope, with a stream ravine running north to south about 30 metres to the east, a detail that would have mattered to whoever chose this position. Earthworks of this kind are generally referred to as ringforts, the most common monument type in the Irish landscape, typically dating from the early medieval period (roughly 500 to 1100 AD) and understood to have served as enclosed farmsteads for people of some local standing. At Drumdartan Glebe, the defining bank survives best along the northern arc, where it reaches about 3 metres in width, with an internal height of 0.8 metres and an external height of 0.7 metres. Elsewhere, the bank has been reduced to a scarp, still readable in the ground but worn down to between 1.2 metres at the west and 2.2 metres at the south. An external fosse, the ditch that typically ran outside such an enclosing bank, survives along the southern and western sides, ranging from 5 to 8 metres wide at the top and between 0.3 and 0.7 metres deep. Four mature deciduous trees grow along the north-western to north-eastern stretch of the bank, a planting that may itself be centuries old, since trees on fort banks were often considered significant or protective in local tradition. Traces of an outer bank, 4 to 5 metres wide and only 0.3 to 0.5 metres high, survive along the south-south-east to west-north-west arc. No original entrance has been identified.