Its enclosing bank, once a proper earthen wall, has been worn down to little more than a scarp across much of its arc, partly through centuries of cattle moving over it, partly through farmers dumping field-clearance debris inside. What was engineered to separate a household from the landscape has, over time, been absorbed back into it.

A ringfort, sometimes called a rath, is a roughly circular enclosure defined by one or more earthen banks and ditches, built mainly during the early medieval period in Ireland as a farmstead or settlement boundary. The Garrynoe example is a small one, measuring roughly 18 metres across from north-west to south-east and 16 metres in the other direction. Around it runs an outer fosse, the trench that would originally have provided both drainage and a degree of defence, though much of it has since been filled in and is now only visible along the northern and eastern arcs. A causewayed entrance, a gap where the fosse was bridged to allow passage, sits at the south-east, and the interior slopes gently downward from west to east, following the natural fall of the hillside. A separate, smaller gap in the north-east of the bank, about a metre wide, reads now as a later opening made for livestock rather than part of the original design. The site was already cut through by a field boundary by the time the six-inch Ordnance Survey mapped the area in 1843, indicating that agricultural reorganisation had begun encroaching on its form well before the modern period. The upland setting, east-facing with open views to the north, east, and south, suggests whoever chose this ground was more interested in prospect and drainage than concealment.