An L-shaped wedge of earthen platform, roughly twenty metres across at its widest, sits on a gentle rise in low-lying grassland, surrounded by hills on all sides. To the west, a shallow depression, a fosse or external ditch, roughly four metres wide and less than half a metre deep, is just about legible in the ground. Everything else is gone.

A ringfort, or rath, is one of the most common monument types in Ireland, an enclosed farmstead of the early medieval period typically defined by one or more circular earthen banks and ditches. What makes the Tyfarnham example notable is precisely how little of it remains. When the Ordnance Survey mapped the area in 1837, the site was still recognisable as a roughly circular earthwork and was marked on the Fair Plan map with the annotation "fort". At some point after that, the bulk of the monument was quarried away, most likely for the material itself, a fate that has claimed a significant number of similar sites across the Irish midlands. The quarrying has left only this L-shaped remnant, a scarp edge where the bank once curved, with the faint fosse just surviving on its western side.