Rather than building from scratch, they worked with the landscape, cutting and shaping the earth into what is now a large, round-topped mound, slightly flattened at its crest and measuring roughly 31 metres north to south and 38 metres east to west. The result is a rath, the Irish term for a ringfort, which was the standard form of enclosed farmstead used across early medieval Ireland, typically from around the fifth to the twelfth century. Most were built on level ground; this one occupies a commanding upland position, using the ridge itself as part of the design.

What gives the site its particular character is the way the enclosing scarp, a steep cut face of earth rather than a built wall, rises to around 3.5 metres on the western side. It sweeps from south through west to north, giving the interior a strong, defended edge on the approaches most exposed to the prevailing ridge-line. On the eastern side, where the natural slope of the ground meets the level of the interior, there is a possible entrance gap, the kind of subtle feature easily missed in the field but significant in understanding how the site was used. The topography effectively does the work that elsewhere required a raised bank or ditch.