The wall does not know, or does not care, that it is sitting on top of an early medieval cashel, the term for a stone ringfort, a type of enclosed farmstead that once dotted the Irish countryside in considerable numbers and served as the defended homestead of a farming family or minor lord.

The cashel at Lissalondoon is almost perfectly circular, measuring roughly 47.5 metres north to south and 46.5 metres east to west. What remains of its defining drystone wall, that is, a wall built without mortar, relying entirely on the careful stacking of stone, survives to an internal height of only about half a metre on the eastern side, where it is around 2.7 metres wide. Elsewhere the original structure has dissolved almost entirely into a grassed-over bank of earth and stone, the kind of low undulation that a casual glance might mistake for a natural rise in the ground. The later field wall, laid over the cashel's arc from the south-west through north to east-north-east, speaks to generations of agricultural reuse, the old boundary quietly buried beneath the practical demands of whoever farmed here next.