Sit on the grass of the gentle western slope of Carrigadoon Hill and you would feel nothing unusual beneath you, see nothing but ordinary pasture rolling across gently undulating ground. The enclosure, along with a companion structure directly adjoining it, exists as a fact of the landscape without any surface trace whatsoever.

What revealed it was an aerial photograph taken by the Air Corps, reference V. 312/3077/6, which captured the faint cropmark signatures that betray buried or levelled enclosures when seen from above. Cropmarks form when buried features, such as the filled ditches or compacted banks of an old enclosure, cause the vegetation above them to grow differently, either more lushly or more sparsely, depending on the underlying archaeology. From ground level the effect is invisible; from the air, in the right season and lighting, a pattern emerges. In this case the photograph identified two conjoined enclosures, structures that share a boundary, sitting on a natural terrace partway along the slope. The relationship between the two, whether one predates the other or whether they were contemporary, is unknown.