On almost every side, the ground drops away steeply into the valley below, meaning the site needed little artificial reinforcement to present a formidable face to the outside world. Only to the west does the land stay level, and that is precisely where the entrance was placed.

Ringforts, known in Irish as raths, were the most common form of enclosed settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. They served as farmsteads for a single family or small community, with the enclosing bank and ditch providing security for livestock as much as for people. The Slaheny example is roughly circular, measuring 22.5 metres north to south and 20.5 metres east to west. What makes it structurally interesting is its layered western defences: a bank some 10.7 metres wide, a fosse, or defensive ditch, between it and an outer bank, all concentrated along the one arc where the natural topography offered no steep drop to do the work instead. The main scarp, around a metre high, is defined clearly, and a further fosse roughly 1.8 metres wide is visible to the south-west and west-north-west. A modern field boundary running north to south just outside the western entrance has likely clipped and disturbed the banks and ditches along that arc, so what survives there is probably less complete than it once was.

The interior is level, and the whole site is now densely overgrown, sitting within woodland that has done as much to preserve it as to obscure it. The vegetation makes the earthworks harder to read at a glance, but it also means the site has not been ploughed out or levelled, a fate that has claimed a significant proportion of Ireland's ringforts over the past century of intensive agriculture.