The enclosure at Carrownaglogh measures roughly 26 metres north to south and 27 metres east to west, making it a fairly modest sub-circular space, slightly raised above the surrounding pasture and ringed by an earthen bank. That bank varies in both height and width depending on where you measure it, rising to about 1.35 metres on the north-east side and narrowing to around 1.8 metres across on the north-west. None of this would be especially remarkable, except that nobody is entirely sure what the structure actually is.

Local tradition holds that the enclosure was put up within living or near-living memory, no more than a few generations back, to serve as a cattle corral. It is the kind of practical, improvised feature that farmers across Ireland have built and rebuilt for centuries, and the stone facing along the bank could support that reading. But that same stone facing complicates things. It may not be original; it may instead reflect the enclosure being absorbed into a later system of field walls, with stones added as boundaries were reorganised around it. If that is what happened, the underlying earthwork could be considerably older. A rath, the term for a roughly circular bank-and-ditch enclosure typical of early medieval Ireland, often associated with farmsteads dating from roughly the fifth to the twelfth centuries, would fit the dimensions and form well enough. The honest answer is that the structure has characteristics consistent with both possibilities, and no excavation appears to have resolved the question.