Most ringforts and enclosures in Ireland aim for a complete circuit, the better to define a boundary and project a sense of enclosure. This one is only half there. The earthen scarp that marks its edge runs along the eastern and southern sides, reaching about seventy centimetres in height for most of its arc but rising to around a metre and a half at the south-west. The northern side, where the natural rise of the ground may have done some of the work, is simply absent, or at least no longer visible.

The earthwork's surviving elements are modest but legible. A fosse, the flat-bottomed or V-shaped ditch that typically accompanies an enclosure bank, runs along the eastern, southern, and western sides, measuring roughly four and a half metres wide and about seventy centimetres deep. Beyond it sits an external bank, now eroded and largely obscured by vegetation, with possible traces of a second, slighter bank visible for about ten metres at the south-east. Together these features suggest something that was once more elaborate than it now appears, a multi-vallate arrangement, meaning one with more than one encircling bank or ditch, which in Irish archaeology tends to indicate a site of some social significance, whether a high-status farmstead, a ritual space, or a boundary marker of local importance. The exact date and function of this particular enclosure remain unresolved. What is clear is that it did not stand alone in this landscape: a related earthwork survives roughly 420 metres to the north-north-east, and a further enclosure lies some 800 metres to the east-north-east, suggesting that the fields around Lacken were once considerably more organised and inhabited than the present pasture implies.