It sits on top of a drumlin, one of those smooth, egg-shaped hills of glacial till that pattern so much of the Irish midlands and northwest, and from the air its outline is clear enough. On the ground, the picture is considerably murkier.

A rath, as this type of enclosure is also known, is a roughly circular earthwork built during the early medieval period, typically enclosing a farmstead and its inhabitants. The Drumkeelan More example is subcircular rather than a perfect ring, measuring around 29 metres east to west and 26 metres north to south. Its defining earthen bank is overgrown and, in places, has been absorbed entirely into the surrounding field boundary, running south, west, and north as a continuous farm wall. On the eastern side it has worn down further still to a simple scarp. The outer fosse, a shallow defensive ditch that would once have reinforced the bank, survives along the northern, eastern, and southern arc, though it is modest in scale: less than two metres across at its base and only about twenty centimetres deep. The original entrance has not been identified, which is not unusual where centuries of agricultural activity have reworked the landscape around and even through a monument. What makes this site particularly interesting to archaeologists is the absence of any cartographic record. The feature was identified not through historical maps but through aerial photography, meaning it slipped past successive generations of surveyors without leaving a mark on paper.