The ring-ditch at Lannagh leaves no visible trace on the ground; no mound, no hollow, no stone. It exists, for now, as a cropmark, the kind of subtle discolouration in growing vegetation that reveals a buried ditch beneath the soil when aerial or satellite imagery is captured at precisely the right moment in the agricultural season.

A ring-ditch is the buried remnant of a circular trench, most commonly associated with prehistoric funerary or ritual monuments. In many cases they represent all that survives of a round barrow, the original earthen mound having been ploughed flat over centuries of cultivation, leaving only the enclosing ditch as a ghostly outline beneath the field. The Lannagh example, defined by a single continuous ditch forming a near-perfect circle, was first identified by Jean Charles Caillére and became visible through iMAPS imagery captured in 2022. Given its modest diameter and the flat, agricultural character of the surrounding landscape, it is the kind of site that could have remained unrecorded indefinitely without the patient scrutiny that aerial survey makes possible.