Fort, Dernasmallan, Co. Leitrim

A drumlin is a smooth, elongated hill formed by glacial deposits, and in Leitrim they ripple across the landscape in long parallel ridges. This particular fort occupies the east-facing slope of one such NE-SW ridge, a position that would have offered a commanding view over lower ground, though today the earthworks speak more to quiet obscurity than any obvious imposition of authority.

The enclosure measures approximately 28 metres north to south and 17.5 metres east to west internally, giving it a compact but not insignificant footprint. What defines it most clearly on its western side is an earthen bank, nearly eight and a half metres wide and standing up to two metres on its outer face, accompanied by a flat-bottomed fosse, the term used for the ditch that typically runs outside such a bank. That fosse is up to nine metres wide at the top and around a metre to a metre and a half deep, dimensions modest enough to suggest enclosure and boundary-marking rather than heavy-duty military defence. On the northern and eastern sides, later agricultural field banks have overlaid or replaced whatever original perimeter existed, and to the south and north-west a further field bank circumscribes the site, making it difficult to read the fort's full original extent. No entrance has been identified, which is itself an oddity; most earthwork enclosures of this type preserve at least a gap or causeway across the fosse that hints at where people once passed through.