The feature shows up as a cropmark, a phenomenon where buried ditches or banks alter the growth rate of the vegetation above them, leaving faint rings or lines visible only from the air under the right conditions, typically during a dry summer when crops over disturbed soil grow differently to those rooted in undisturbed ground.

What the aerial photograph reveals is a roughly circular feature, most likely defined by a fosse, which is a defensive or boundary ditch dug around a settlement or enclosure. The estimated maximum diameter is around 35 metres, placing it within the range typical of a small ringfort or enclosed farmstead of early medieval date, though no firm dating has been established for this particular site. It was identified through a survey of the Ballinrobe district, an area of south Mayo lying between Lough Mask and Lough Carra, two limestone lakes with their own considerable archaeological surroundings. The landscape here is one where ancient occupation has left marks at many scales, some dramatic, some so faint they require an aircraft and a dry July to become legible at all.