Neither the 1840 six-inch edition nor the 1897 twenty-five-inch edition of the OSi maps records anything at this spot, which is a curious absence given how thoroughly those surveys documented the Irish landscape. The feature only surfaces on the later Cassini edition of the OSi six-inch map, where it appears as a raised, semi-circular area, roughly 25 metres on its northeast-to-southwest axis and 17 metres northwest to southeast, defined by a scarp, essentially a sharp break in the slope of the ground, running from the northeast around through south to the southwest.

The reasons for its omission from the earlier maps are not recorded. It may have been less legible on the ground in those decades, obscured by vegetation or agricultural disturbance, or it may simply have been passed over by surveyors who did not consider it sufficiently distinct to mark. Earthworks of this general character, raised platforms or enclosures defined by scarps rather than built-up banks, can be difficult to categorise with confidence. They might represent the remains of a ringfort, a form of enclosed farmstead common in early medieval Ireland, or something else entirely. Without excavation, the date and function of the Garryarthur feature remain open questions. What has since been noted, by Martin Fitzpatrick who compiled the record in November 2021, is that a faint circular cropmark is visible on Google Earth satellite imagery, a trace that appears when differences in soil depth or moisture cause vegetation above a buried feature to grow differently from its surroundings.

The site sits in upland pasture approximately 100 metres north of a large forestry plantation, which serves as a useful landmark when trying to orient yourself on the ground. Because the earthwork is subtle, and because its character changes with the season, it rewards a visit in dry summer conditions when cropmarks tend to be most pronounced, though the raised area and scarp should be readable underfoot at most times of year. The land is agricultural, so the usual courtesies apply when approaching across farmland. The Google Earth orthoimages mentioned in the survey record are a practical starting point for getting a sense of the feature's shape before visiting, since what you are looking for is less a dramatic monument than a quiet irregularity in the pasture, one that two nineteenth-century surveys quietly walked past.