A few irregular depressions in the pasture, a scattering of gorse, and a faint outline detectable only on aerial photography are all that remain of what was once substantial enough to be marked on the 1837 Ordnance Survey Fair Plan map as a roughly circular, tree-planted earthwork labelled simply 'Fort'. By 1971, a field inspection found no surface remains whatsoever. The site belongs to that peculiar category of Irish archaeological record: a place that is easier to find on a nineteenth-century map than in the landscape itself.

Ringforts, known in Irish as raths, were enclosed farmsteads typically dating from the early medieval period, built from earthen banks and ditches to define a domestic space and protect livestock. They were once extraordinarily common across Ireland, numbering in the tens of thousands, though centuries of agriculture have reduced many to nothing. The Portaneena example carries an additional layer of ambiguity. The tree planting visible on the 1837 map raises the possibility that the original earthwork was repurposed as an ornamental tree-ring in the nineteenth century, likely in connection with Easthill House, a property located around two hundred metres to the south-southeast. It would not be unusual for landowners of that period to incorporate existing earthworks into designed landscapes, either by planting within them or by using their raised outlines as a ready-made feature. Whether the ringfort's banks survived long into that arrangement, or were cleared during the same period of improvement, is no longer possible to say.

The site sits in pasture on a NE-facing slope with open views to the northeast and east, and Killinure Lough visible to the west. That elevated, outward-looking position is itself characteristic of early medieval settlement choices, where visibility across the surrounding countryside carried both practical and social significance. What the hill once held is now largely a matter of inference, traced between an old map annotation and a ghostly crop mark visible only from above.