In a flat field of tillage land squeezed between the M1 motorway and the R132, a circular earthwork roughly twelve metres across lies completely invisible at ground level. The only way to see it is from the air, where it appears as a cropmark, a faint ghostly ring pressed into the soil that shows up because the buried ditch beneath affects how the crops above it grow.

A cropmark forms when a filled-in ditch or pit, which retains more moisture than the surrounding subsoil, causes the vegetation above it to grow taller or ripen at a slightly different rate. Viewed from altitude under the right conditions, these subtle differences in colour and height resolve into shapes, and those shapes can reveal the outlines of structures that vanished from the surface thousands of years ago. The feature at Lissenhall Little was recorded by the Cambridge University Collection of Aerial Photography as reference BDS 49, and is also visible on Bing satellite imagery. Ring-ditches of this kind are typically interpreted as the remains of prehistoric burial monuments, often Bronze Age round barrows whose central mound has long since been ploughed flat, leaving only the encircling ditch as evidence. The record was compiled by Geraldine Stout and updated by Christine Baker, with the site uploaded to the record in January 2015.

There is no formal access point, no signage, and nothing to see from the roadside. The site sits on private agricultural land between two busy roads, and the cropmark itself is only legible from above. The best a curious visitor can do is consult the aerial sources already on record, or examine the relevant satellite imagery online, where the ring can occasionally be made out depending on the season and the state of the crop. Its presence is a reminder that the landscape around the northern Dublin commuter belt, so thoroughly reshaped by roads and development, still carries older arrangements just beneath the surface.