That slight curve in the tarmac is not an accident of surveying; it follows the ghost of a much older circle, an earthen enclosure that has been quietly absorbing the landscape around it for centuries while the landscape, in turn, has been absorbing it back.

The enclosure at Wherrew sits on a low hill where the peninsula narrows before pushing westward into the north-eastern corner of Lough Conn, with the River Deel entering the lake roughly 200 metres to the north-west and a small bay opening to the south. It is a subcircular earthwork, around 60 metres across, defined by a broad earthen bank of the kind commonly associated with early medieval settlement or enclosure in Ireland, though no date is attached to this particular example. The 1838 Ordnance Survey six-inch maps record it clearly as a roughly circular form, and they also show a smaller subcircular feature, about 20 metres in diameter, sitting within the interior near the south-eastern bank. By the 1922 revision that inner feature had disappeared from the map, and it is no longer traceable on the ground. In the intervening centuries, later rectangular field boundaries were laid straight across the older, curved monument: fences clip the east, south, and west sides of the enclosure, and at one point a field fence merges directly into the bank's outer face. The road to the south appears to have been routed with some awareness of the old circuit, producing that telltale kink.

What survives of the bank is broad but low, between three and four metres wide and rarely more than a metre high on its exterior face, and much of even that is buried under dense thorn and bramble. Where the vegetation clears, in the south-western quadrant, there are two heaps of field-clearance stones and shallow depressions in the interior floor that hint at subsurface features. The enclosure is the kind of monument that rewards patience and a good eye for ground-level irregularities rather than any dramatic revelation; its most legible feature, in the end, may be the road that bends politely around something it cannot quite name.