The one at Cashelfean, in West Cork, presents a different problem: it was built into a north-facing slope, which meant that simply throwing up a circular earthen wall would have left the interior uneven and partly waterlogged. The solution was to raise the ground inside the northern arc by 1.75 metres, effectively levelling the floor of the enclosure against the pull of the hillside. It is a small engineering decision, but it tells you something about the care that went into these structures.

A rath, to use the Irish term, is a type of ringfort defined by its earthen rather than stone construction. Thousands survive across Ireland, most of them dating from the early medieval period, roughly the fifth to the twelfth centuries, and the majority were farmsteads rather than fortifications in any military sense. The bank at Cashelfean is a solid example of the form: the enclosure measures approximately 28 metres north to south and 27.5 metres east to west, with an external bank height of up to 2.1 metres and an internal height of around 1.45 metres. The inner face of that bank has worn away along its north-western to north-north-eastern arc, which is not unusual given that this is precisely the side most exposed to weather and to the gradual creep of soil down the slope. What remains sits in pasture, quiet and largely unremarked, holding its artificial platform level against the gradient of the hill.