The field system buried beneath that surface, however, stretches across at least nine hectares and has never appeared on any Ordnance Survey historic map. It exists, for most practical purposes, only from the air.

The site first came to light during the Bruff aerial photographic survey of 1986, when a series of linear and slightly curvilinear cropmarks were identified in the soil (recorded as Bruff 269.02, AP 4/3711). Cropmarks form when buried features, walls, ditches, or compacted surfaces, affect how vegetation grows above them; in dry summers especially, grass over buried stone grows thinner and yellower, while ditches retain moisture and stay greener, tracing the outlines of vanished structures on the ground. At Ballyhoodane, those outlines run approximately east-northeast to west-southwest for roughly 445 metres, with shorter cropmarks intersecting at right angles, suggesting a network of small rectilinear fields. Later orthoimagery taken between 2005 and 2013 confirmed the anomalies, and a Google Earth image captured on 6 February 2018 shows the pattern most clearly of all, with the intersecting lines resolving into recognisable field boundaries south of a ring-barrow, a low circular earthen mound typically associated with prehistoric burial, recorded separately as LI023-288. An enclosure, LI023-041, lies within the eastern portion of the area. The research was compiled by Alison McQueen and Vera Rahilly and uploaded to the record in September 2020.

There is little to see on the ground itself, which is part of what makes this kind of site genuinely interesting. The field system is most legible through the aerial images referenced in the archaeological record, particularly the Google Earth orthoimage from February 2018, which can be examined before any visit. The surrounding landscape is private farmland, so access would require permission from the landowner. For anyone drawn to the archaeology of invisible places, the Ahnavar streamside setting and the proximity of the ring-barrow and enclosure suggest that this corner of County Limerick was once a good deal more organised and occupied than its present quietness implies.