At Lea More in County Offaly, there is a possible enclosure that cannot be seen by anyone standing on the ground above it. Its presence, such as it is, was detected only from the air, and even then with considerable uncertainty about whether it represents human activity at all.

The site was identified from aerial photographs taken in 1973, in a series held under the reference GSI, N 517/16. Aerial photography has been one of the most productive tools in Irish archaeological survey, capable of revealing the ghostly outlines of ditches, banks, and field systems that have been ploughed flat or buried over centuries; crop marks and soil discolouration can betray what is invisible at eye level. In this case, however, whatever pattern the photographs captured was not persuasive enough to confirm the site as genuinely ancient. It is formally described as being of doubtful antiquity, which in archaeological terms is a significant qualification. The feature may be a remnant of historic land use, a natural soil variation, or something else entirely that mimics the circular or sub-circular form typical of an enclosure, the general term for a defined area bounded by a ditch, bank, or wall, which in Irish prehistory and early medieval periods served purposes ranging from settlement to ritual to agriculture.