The site in Aghavadrin sits in what remains of Dumb Lough, a lake whose water level has been lowered so considerably over time that the artificial island no longer has any water around it at all, having merged quietly with the mainland. It measures roughly twelve metres in diameter and presents itself as a gently rounded, vegetation-covered rise among the rushes, unremarkable to anyone passing without context.

This is a crannog, a type of artificial or partially artificial island settlement built in lakes, rivers, or wetlands, typically during the early medieval period in Ireland, though some were constructed earlier or used considerably later. They were defensive by nature, the surrounding water serving as a barrier, and they were often home to high-status families or used as places of refuge. The Aghavadrin example was recorded on all editions of the Ordnance Survey maps, suggesting it was a consistent, recognisable feature of the landscape across the nineteenth and twentieth centuries. When O. Davies surveyed it for the Irish Tourist Association in 1942, he recorded one probable pile projecting at the edge, a single surviving timber element hinting at the original wooden construction beneath the accumulated soil and vegetation. Around 250 metres to the north-east lies a second possible crannog, suggesting that Dumb Lough, when it held water, may have supported more than one island settlement.