The island is a crannog, one of those artificial or partly artificial lake dwellings built and inhabited across Ireland from the early medieval period onwards, constructed by piling timber, stone, and brushwood into shallow water to create a secure, defensible platform for habitation. The lake that once surrounded it, Corfin Lough, has almost entirely silted up, leaving the crannog stranded in what is now a marshy basin rather than open water.

Ordnance Survey maps from 1834 and again from 1907 both show Corfin Lough as a sub-rectangular body of water, roughly 600 metres from east to west and between 230 and 400 metres from north to south. In both editions, the crannog appears clearly as a small island at the lake's centre. Even then it was an island; now the water that gave it meaning and protection is largely gone, replaced by accumulated sediment and wetland vegetation. The crannog itself survives as a roughly circular mound about 30 metres in diameter, covered in grass, scrub, and trees, its outline still legible in the landscape even if the context that made it remarkable has quietly drained away over the intervening century.

The site has been recorded as impossible to reach, which is perhaps fitting for something originally designed to be difficult to access without a boat. The silted terrain around it offers no easy approach, and the scrub and tree cover mean there is little to see even from a distance. What remains is less a monument than a curiosity, a place where two editions of a Victorian map and a slowly vanishing lake together preserve the outline of a way of life that predates both by many centuries.