It would be easy to walk past it without a second thought. But the oval shape, roughly thirty metres at its longest, is the outline of a rath, an early medieval farmstead enclosed by an earthen bank and a shallow external ditch, the kind of settlement that was once a familiar feature of the Irish countryside and that still turns up, quietly, in fields across the country.

The enclosure at Glennaknockane measures approximately 29.6 metres on its north-east to south-west axis and 22.2 metres across. The earthen bank survives to an internal height of around 0.8 metres and a slightly more pronounced external height of 1.1 metres, with an outer ditch, or fosse, running from the west around to the north-north-east and dropping to a depth of about 0.3 metres. There are two gaps in the bank, one to the east-south-east at roughly 2.3 metres wide and one to the west at around 2 metres, suggesting where original entrances may once have been. The site was already recorded on Ordnance Survey six-inch maps by 1904 and again in 1936, marked in the characteristic hachured style used to indicate earthwork enclosures. Close to the west of the ringfort lies a souterrain, an underground stone-lined passage or chamber, often associated with nearby settlement sites and thought to have served for storage or as a place of refuge. The proximity of the two features in the same landscape strongly suggests they formed part of the same early medieval occupation of this hillside.