On a bluff along the eastern face of a narrow spur of land, with a small canalised stream running close to its eastern edge, sits a low grass-covered enclosure that most walkers would pass without a second thought. Its clearest historical appearance is on the 1834 edition of the Ordnance Survey six-inch map, where it is marked in gothic script as a "fort", the conventional term used by early surveyors to indicate a ringfort or similar enclosed earthwork of early medieval origin.

Ringforts, known variously as raths or lios across Ireland, were typically circular enclosures defined by an earthen bank and outer ditch, used as defended farmsteads roughly between the fifth and twelfth centuries. The Drumlongfield example fits loosely within that tradition, though time and land use have softened its profile considerably. The enclosure is subcircular rather than perfectly round, measuring roughly 46 metres north to south and just under 40 metres east to west. A slight scarp, essentially a low earthen slope marking the old bank line, is still traceable on the southern side, where it reaches a modest height of about 0.75 metres. To the south-west, faint traces of a fosse remain. A fosse is simply a defensive ditch, and here it survives as a shallow depression, its interior depth measured at around 0.7 metres, its top width stretching to over ten metres, suggesting it was once a more substantial feature before centuries of silting and agricultural pressure reduced it to what it is today. The positioning of the site, on a natural bluff above a watercourse, is consistent with the practical logic of early enclosure building, where topography was used to reinforce man-made defences.