It has been sitting there, slowly being absorbed by vegetation and edged up against by fieldbanks on three sides, for well over a thousand years. The gap in its south-eastern arc, about two metres wide and possibly once stone-lined, is likely where people once entered and left.

This is a univallate rath, meaning a ringfort enclosed by a single bank and ditch, the most common type of early medieval settlement in Ireland. Tens of thousands were built across the country, typically between the sixth and tenth centuries, serving as farmsteads for free farming families. The bank at Lacka, though overgrown, remains well defined, rising around 1.2 metres above the interior ground level and two metres above the exterior, which gives a sense of how deliberately it was built up. Its position on high ground is characteristic; the commanding view of the surrounding land would have had both practical and social value, making the enclosure visible to neighbours and offering clear sightlines to whoever lived within it. The abutting fieldbanks to the north, west, and east suggest the landscape around it has been continuously farmed, the later boundaries of agriculture pressing in close against this much older one.