The site is known as Lisfurnel, a name old enough to have been recorded on the Ordnance Survey six-inch maps of both 1840 and 1916, where it was carefully hachured and labelled, suggesting it was a recognisable feature of the landscape long before modern heritage classification caught up with it.

What survives is a rath, the most common type of early medieval Irish settlement monument, essentially a circular enclosure defined by an earthen bank and an external ditch, used as a farmstead or residence typically between the sixth and tenth centuries. At Lisfurnel the bank is round-topped and still stands between one and just over two metres above the surrounding ground on its outer face, though it has been worn down to a simple scarp on the southern side. The ditch, or fosse, running around the outside, is steep-sided with a flat base and varies considerably in width, from just over a metre to as wide as seven metres in places. Most telling is the entrance: a two-metre gap in the bank at the north-north-west aligns precisely with a causeway of the same generous width across the fosse, preserving the original route by which people and animals once passed in and out. The interior measures roughly twenty to twenty-two metres across, a modest but functional space. The enclosure sits on a ridge aligned north-east to south-west, about a hundred and thirty-five metres south of the Owennaranny River, a position that would have offered both a degree of elevation and proximity to water.