At the crest of a northeast-facing slope in Tinnalyra, County Waterford, a roughly circular patch of grass sits enclosed by earthworks that most passers-by would take for a natural rise in the ground. It is only when you begin to read the landscape more carefully that the geometry becomes apparent: a near-perfect subcircular area, roughly 48 metres east to west and 45 metres north to south, bounded by a substantial earthen bank and, beyond that, a wide flat-bottomed fosse. A fosse, in this context, is simply a defensive ditch dug to complement an enclosing bank, the pair working together to define and protect whatever lay within.

The enclosure's dimensions are not modest. The inner earthen bank ranges from five to nine metres wide, and its exterior face still rises between 2.7 and 3.9 metres above the base of the fosse, a considerable height for an earthwork that has had centuries of vegetation and weathering working against it. The fosse itself is up to twelve metres across at the top and between 0.8 and 1.6 metres deep. On the southwest to west side, the fosse is stone-revetted, meaning its sides were faced with stone to hold the cut, which suggests it was at some point re-cut or cleaned out, a sign that the enclosure was actively maintained rather than thrown up and forgotten. A secondary outer bank survives on the southeast to southwest arc, though it has been absorbed into a later field boundary on the northeast side and disappears elsewhere. A formal entrance breaks through both the inner and outer banks at the southeast, the inner gap measuring just under three metres wide and the outer slightly narrower at two metres.

What exactly this enclosure enclosed is not recorded. The term "embanked enclosure" covers a broad range of possibilities in Irish archaeology, from early medieval settlement sites to ceremonial or stock enclosures, and the evidence at Tinnalyra does not point firmly in any one direction. The care taken with the stone revetment and the deliberate entrance alignment suggest something more considered than a casual agricultural boundary, but the site has not been excavated, and its original function remains genuinely open.