Tucked into what is now the south-western corner of a gravel car park within Anacotty Industrial Estate, the site carries the quiet distinction of being, in all likelihood, a monument to cartography rather than to any earlier human endeavour.

The story begins with the Ordnance Survey's early nineteenth-century mapping of Ireland. When the OS six-inch map was produced in 1838, the feature at Grange Upper was already being treated with scepticism, recorded as a non-antiquity rather than a prehistoric earthwork. The map shows a circular area of approximately thirty metres in diameter, with a trigonometrical station, one of the precisely positioned survey points used to establish accurate measurements across the landscape, marked at its centre. The working theory, noted by compilers Fiona Rooney and Martin Fitzpatrick, is that the low mound was constructed by the Ordnance Survey itself as a stable base for that trig station, which recorded a spot height of 125 feet above ordnance datum. By the time the OS twenty-five inch map was published in 1897, only the northern to south-eastern arc of the raised area remained, with the rest absorbed into a field boundary; a quarry had also appeared some twenty metres to the west, which may account for some of the disturbance. Subsequent aerial imagery, including Digital Globe orthoimages from 2011 to 2013 and Google Earth captures from 2018, confirmed that no surface trace of the feature survives at all.

There is, in practical terms, nothing to see at Grange Upper today. The topsoil has been stripped and a gravel surface laid across the area where the earthwork once stood, thoroughly erasing whatever modest relief remained. For anyone curious enough to visit Anacotty Industrial Estate on the outskirts of Limerick city, the interest lies entirely in the idea of the place rather than anything visible on the ground: a circle on a Victorian map, a surveyor's mound pressed into service as a monument by the mere act of being recorded, and then quietly swallowed by industrial development before anyone could decide what it actually was.