That name is telling. In Irish, a lissan or lios refers to a circular enclosure, a word more often associated with ring forts than burial monuments, and it suggests that local memory attached its own meaning to this feature long before any archaeologist came to measure it.

The monument is a ring barrow, a type of prehistoric funerary enclosure typically dating to the Bronze Age, in which a central area is bounded by a circular ditch, known as a fosse, and an earthen bank thrown up from the excavated material. Here, the circular area measures roughly 5.18 metres across, enclosed by a fosse approximately 0.6 metres deep and an external bank that stands around 0.7 metres on its inner face and 0.5 metres on the outer. The bank has been levelled along its north-eastern to south-eastern arc, and there is a gap to the west-north-west, which may represent an original entrance or simply the result of long agricultural use. The field name 'An Liosan' was recorded by Bowman in 1934, preserving a layer of vernacular identification that sat alongside the land for generations before the earthwork was formally catalogued.