The enclosure, roughly fifty metres across and subcircular in shape, was recorded on the first edition Ordnance Survey six-inch map of 1838, but by the time fieldworkers went looking for it in May 1984, not a single surface trace remained. What the nineteenth-century cartographers had captured, and what subsequent aerial photography has confirmed, is a feature that the landscape itself has quietly swallowed.

Enclosures of this kind, typically the remains of a ringfort or a similarly bounded settlement, were once common across Ireland. They were built from earthen banks or stone walls to define a farmstead and provide some degree of protection, and they appear across the Irish landscape in their thousands, in varying states of survival. This one measured approximately fifty-three metres on its northwest to southeast axis and around fifty metres northeast to southwest, placing it within the normal size range for a domestic enclosure. At some point after the 1838 mapping, a north to south field boundary was cut through it, running from roughly the northeast to the southeast of the circuit, fragmenting whatever remained of its form. That kind of incremental agricultural clearance, repeated across generations and across the country, accounts for a great deal of what is now missing from the visible record.

What makes the Lissaniska site quietly interesting is the gap between its invisibility on the ground and its legibility from above. Aerial imagery captured in 2019 shows the outline of the enclosure as a cropmark or soil-mark, the buried remnants influencing vegetation or drainage in ways that only become apparent at altitude. The hillock that once gave the enclosure its commanding position in the landscape still exists; the enclosure itself survives only as a shadow, readable in the right light and from the right distance.