This kind of feature, known as a cropmark, appears when buried ditches or banks cause the plants growing over them to ripen at a different rate from the surrounding vegetation. What makes the Blackland enclosure particularly interesting is not just that it survives at all, but that it appears to have been swallowed by a later landscape: one of the boundaries of an adjacent field system cuts directly through it, suggesting the enclosure was already old, perhaps already abandoned, when whoever laid out those fields decided it was no longer worth working around.

The site came into sharper focus in 2012, when the Discovery Programme's LIARI Project, a geophysical survey initiative designed to record buried archaeological features across the Irish landscape without excavation, identified not only the main circular enclosure but evidence of successive enclosures and associated field boundaries in the same area. Aerial photographs catalogued under the reference FSI 423/2 had already flagged the cropmarks, and the subsequent ground survey added considerable detail. Archaeologist Dowling, writing in 2013, noted that the enclosure's relationship to the surrounding field system points strongly to it being a pre-existing feature, one that the later agricultural layout absorbed rather than erased entirely. Circular enclosures of this kind are common across Ireland and are variously associated with settlement, burial, or ritual activity from the prehistoric through to the early medieval period, though without excavation the precise date and function of the Blackland example remain open questions.

The site lies within agricultural land, and there is no formal public access or marking of any kind on the ground. Practically speaking, the enclosure is not something a visitor can see with the naked eye from field level; the terrain is only gently undulating, sloping slightly to the south and east, with open views stretching south towards Howth Head. The cropmark phenomenon is most visible from aerial vantage during dry summer conditions, when soil moisture differences become pronounced. Those with an interest in the landscape archaeology of the greater Dublin area would find the site most rewarding in the context of the broader LIARI survey data, which is accessible through the National Monuments Service record under the reference DU008-052003-.