The ringfort at Dunmore sits on an east-facing slope, and what was once a neatly circular earthwork, roughly 33 metres across from north to south, has been partially swallowed by a later trapezoidal field system. The two structures now overlap in a way that makes it difficult, at a glance, to tell where the early medieval monument ends and the post-medieval farmland begins.

Ringforts, known in Irish as raths when they are made of earth, were the most common form of enclosed settlement in early medieval Ireland, typically serving as defended farmsteads for a single family and their livestock. The Dunmore example follows the earthen tradition: a low bank, still standing to about 1.1 metres in height, traces the original perimeter from the south-southeast around to the northeast, accompanied by a shallow external fosse, the technical term for a ditch dug to reinforce the bank. The interior has not fared particularly well, with rubble and stones dumped there at some point, which may account for why the site reads more as an inconvenience to agriculture than as anything worth preserving. Locally it is still called simply "the fort", which is a small piece of continuity in itself, suggesting that people in the area have long sensed there was something deliberate about the rise in the ground, even if the specifics have blurred over the generations.