On the broad, rounded summit of a hill in Carrickphilip, County Waterford, a roughly circular patch of ground quietly holds its shape against the gradual work of time. What makes it worth pausing over is the layering: this is a tri-vallate enclosure, meaning it was once defined by three concentric lines of defence, bank upon bank, fosse upon fosse. That degree of elaboration is relatively uncommon and suggests the site once mattered considerably to whoever built and used it.

The enclosure was already old enough to be treated as a fixed landmark when the Ordnance Survey recorded it on their six-inch map in 1840. By that point it was mapped as tri-vallate, though what survives on the ground today is the inner subcircular area, roughly 38.5 metres east to west and 35 metres north to south, enclosed by a grass-covered earthen bank that still stands between 1.1 and 1.5 metres high internally. The bank itself varies in width, narrowing to about 2.5 metres on the north side and broadening to around 5 metres on the east, and traces of stone-facing survive on both its inner and outer faces. Beyond the main bank lies an outer fosse, a ditch cut into the hillside, separated from an enclosing field bank by a level berm, a narrow shelf of ground between the two features. The entrance gap, just under 3 metres wide, faces to the south-south-east. The overall diameter of the site at its maximum extent is approximately 75 metres, taking in all surviving elements. Enclosures of this kind are generally associated with early medieval settlement in Ireland, functioning as enclosed farmsteads or higher-status residences, though without excavation the precise date and function of this particular example remain open questions.