The marks appear not as raised earthworks but as cropmarks, positive ones, meaning the vegetation above buried features grows slightly differently to the surrounding crop, betraying the lines of boundaries and enclosures that have otherwise vanished entirely from the surface. It is the kind of archaeology that only reveals itself from altitude, in the right season, under the right conditions.

The site sits approximately 1.29 kilometres southeast of the Gracedieu ecclesiastical complex, a cluster of early Christian and medieval religious monuments recorded under the Sites and Monuments Register reference DU007-015001. That proximity is worth pausing on. Gracedieu, in north County Dublin, takes its name from a medieval nunnery, and the wider landscape around it was shaped by centuries of monastic land management and later ecclesiastical landholding. The field system at Thomondtown likely reflects some portion of that longer agricultural story, though the cropmarks themselves offer no firm date. What the imagery compiled by Tom Condit does show, clearly if fragmentarily, is a series of both linear and curvilinear features running to the east and southeast of a nearby enclosure, recorded separately as DU008-118. Linear features typically indicate field boundaries or drainage channels; curvilinear ones often suggest earlier, pre-medieval organisation of the land. An unnamed stream running west to east lies roughly 144 metres to the south, which would have made this ground attractive for cultivation across many centuries.

The site is not accessible as a visitor destination in any formal sense, and there is nothing to see at ground level. The M1 motorway runs approximately 320 metres to the east, and the field itself is working arable land. The cropmarks are visible on Google Earth using the July 2019 imagery, and that is realistically the best view most people will get. For those interested in the broader landscape, the Gracedieu complex to the northwest offers a more tangible focus, and the relationship between that ecclesiastical site and the agricultural traces at Thomondtown gives both a little more meaning when considered together.