It cannot be seen by standing in the field, walking its edges, or pressing a boot into the grass. The only evidence that something is there at all came from an aerial photograph taken in 1974, which captured a cropmark, a faint circular outline made visible from the air when buried features cause the vegetation above them to grow at a slightly different rate or colour than the surrounding ground.

Cropmark archaeology works because buried walls, ditches, or banks disrupt the soil's drainage and nutrient content, and that disruption travels upward into the roots of whatever crop or grass grows above. From ground level, the difference is invisible. From the air, particularly in dry summers when stress on vegetation is greatest, the pattern can appear with striking clarity. The 1974 photograph of Parkstown placed this particular enclosure at the base of a north-west-facing slope, set within the kind of gently rolling pastureland that covers much of Tipperary. Circular enclosures of this type are frequently associated with ringforts, the enclosed farmsteads that were built across Ireland during the early medieval period, roughly between the fifth and twelfth centuries, though without excavation it is impossible to say anything certain about the date or function of this one.

The land around it has been reclaimed, meaning it has been drained, levelled, or otherwise improved for modern agricultural use, a process that often destroys or obscures earlier features at ground level while leaving subsurface traces intact. What remains at Parkstown is, in that sense, a place defined entirely by absence, known only because a single aerial survey happened to pass over on the right day.