At Ardloman in County Tipperary, whoever constructed this small circular fort did exactly that, incorporating the steep natural drop of a ravine into the defensive scheme itself rather than relying solely on built earthworks. The result is a modest but carefully considered enclosure that blurs the line between what was made and what was simply there.

The fort sits in rough pasture on a gently west-facing slope, its roughly circular interior measuring about 17 metres north to south and 16 metres east to west. That is a compact space, not the territory of a major chieftain's stronghold but something smaller and more purposeful. The builders raised an earthen bank on the north-east to south-west arc, still standing to an external height of around 2.25 metres, and backed it with a fosse, the term for the ditch dug to provide material for the bank and to deepen the obstacle facing any would-be attacker. This fosse runs to nearly 6.7 metres wide and 1.5 metres deep. On the south-west to north-east side, however, the builders economised shrewdly: a steep scarp connects directly with the natural gradient of the ravine, which drops some 2.2 metres on its own. An outer bank follows the north-east to south-east arc, becoming very narrow toward the south-west end where the ravine renders it redundant. A gap of about 6 metres at the east-south-east and a possible causewayed entrance of nearly 5 metres at the south suggest the original approach routes. A causewayed entrance is one where a raised strip of ground crosses the fosse rather than a bridge or simple gap, providing a controlled and slightly ceremonial threshold. Today the interior is well colonised by deciduous trees, with conifers planted along the fosse exterior and outer bank on the eastern side, giving the whole enclosure a more wooded character than it would originally have had.