This ringfort in Lissanisky, County Mayo, slipped through entirely, known only through aerial imagery and the sharp eye of an observer on the ground. The earthwork has been levelled at some unknown point in the past, yet its circular form, roughly fifty metres across, can still be read in the slight undulation of the pasture, a ghost impression in the grass on the level crest of a low ridge running northeast to southwest.

A rath is the most common type of Irish ringfort, an enclosed settlement of early medieval date, typically defined by one or more banks and ditches and used as a farmstead by a family of some local standing. At Lissanisky, the bank has long since been reduced to a barely perceptible rise, and a drystone field wall now cuts across the northeastern edge, repurposing the old boundary line as a property division. What draws the eye most readily is an oval hollow just outside the enclosure to the southwest, measuring roughly eighteen metres by ten, which fills naturally with water. Whether it represents the remains of a quarry ditch, a collapsed feature, or simply a low point in the land that the rath builders once exploited is not recorded. Somewhere toward the southwest interior of the levelled enclosure there is a possible souterrain, an underground passage or chamber of the kind commonly associated with early medieval settlement and likely used for storage or refuge. The site was brought to wider notice by Jean-Charles Caillère.

The ridge on which the rath sits commands a broad, open view over rolling grassland in all directions, which would have made it a sensible choice for settlement regardless of period. A drystone wall crossing the northeast of the site is the most visible feature at ground level today, marking where an ancient perimeter and a much later property boundary happen to coincide.