It exists only as a cropmark, a ghostly outline visible from the air when differential growth in crops or grasses betrays the buried remains beneath. Where a circular earthwork once defined a boundary, perhaps the wall of a ringfort or an early farmstead, the soil retains a memory of its own, expressing it in subtle variations of colour and height that are invisible at ground level but legible from above.

The enclosure was identified through aerial photography by Dr. D.D.C. Pochin Mould, a writer, geographer, and aerial surveyor whose work over Cork and Kerry from the mid-twentieth century contributed significantly to the mapping of sites that would otherwise have gone unrecorded. What the photograph revealed is described as univallate, meaning it had a single enclosing bank or wall rather than the double or triple circuits that sometimes surrounded more elaborate settlements. Circular enclosures of this type are among the most common archaeological features in the Irish landscape, generally associated with early medieval occupation, though without excavation it is rarely possible to say more than that. The cropmark at Knockalisheen gives no further detail about what lay within that boundary, who built it, or when it fell into disuse.

Because the site survives only as a subsurface trace, there is nothing to see on the ground. The enclosure belongs to that large and quietly compelling category of Irish archaeological places that are present without being visible, known without being known fully.