The earthen scarp defining its western to north-eastern edge has been cut so vertically, rising between 1.5 and 1.7 metres, that it reads as deliberate and purposeful; but elsewhere the same boundary simply levels off and merges with the knoll's own slopes, as though the builders were working with the hill rather than imposing upon it.

The knoll appears on both the 1838 and 1922 Ordnance Survey six-inch maps under the name Knockcahill, a detail that fixes it as a recognised landmark well before the modern era. The enclosure itself sits at the very summit, forming a roughly circular raised area measuring approximately 12.8 metres east-north-east to west-south-west and around 10 metres north-north-west to south-south-east. Along parts of the scarp, a low internal rim of earth and stone, about 1.7 metres wide, survives; in other sections it has been lost. The knoll slopes sharply to the south and east, and overlooks areas of wetter ground to the north and south-west, which may well have influenced why this particular rise was chosen and enclosed in the first place. Hawthorn trees, long associated in Ireland with boundaries, fairy forts, and the margins of older landscapes, have taken root along the scarp on its northern side, giving the structure a quietly layered presence that is part archaeology, part local ecology.