The ringfort at Kilgarriff is a roughly circular earthwork about 40 metres in diameter, its boundary formed not by a single uniform wall but by a combination of scarps and an outer earthen bank. That bank still rises to around 1.25 metres on its south-western to eastern arc, while the scarps, essentially cut or built-up changes in ground level, range in height from about 0.65 metres to somewhat more on the north-western run. It is a subtle landscape, the kind that rewards a slow walk around the perimeter rather than a glance from a gate.

Ringforts, known in Irish as ráth when they are earthen-banked, were the dominant settlement form in early medieval Ireland, typically dating from roughly the sixth to the twelfth century. They functioned as farmsteads, the enclosing bank and ditch protecting a family and their livestock rather than marking any military fortification in the grander sense. At Kilgarriff, a probable entrance on the eastern side can be read in the landscape as a break in the inner scarp about 2 metres wide, widening to as much as 7.5 metres in the outer scarp, an orientating detail that would have guided people and animals in and out of the enclosure each day. Perhaps the most intriguing feature here is the souterrain recorded in the north-western quadrant. A souterrain is an underground stone-built passage or chamber, typically associated with ringforts and thought to have served for storage, refuge, or both. Their construction required considerable effort and skill, which is a reminder that whoever lived within this modest earthwork was not simply scraping by at the edge of things.