That boundary appeared on the first edition of the Ordnance Survey six-inch map and remains there today, meaning successive generations of farmers have worked around, or rather through, a structure that predates them by well over a thousand years.

The site is a rath, the Irish term for a ringfort, which was the most common form of rural settlement in early medieval Ireland, typically enclosing a farmstead within one or more earthen banks and ditches. At Kilnaneave the earthworks survive as a roughly circular area measuring approximately 32 metres north to south and 28 metres east to west. The defences are double, consisting of two raised curving banks separated by a fosse, which is a rock-cut or earthen ditch, with a further outer ditch beyond the second bank. The dimensions are modest but legible: the inner bank runs about three metres wide, the first fosse nearly five and a half metres, the outer bank just over four metres, and the outermost fosse around three and a half metres. These are not dramatic earthworks, and the banks are described as very slight, but the concentric pattern of the double enclosure is a mark of a more substantial original construction, one that would have signalled a degree of status among early farmers in the area. The rath sits on a south-east facing slope of a hill in hilly pastureland, a position typical of the type, chosen for drainage and modest elevation rather than dramatic defensibility. The defences are said to be most visible at the north-west and east, where the ground has been less disturbed.