When archaeologists visited in 2000, almost the entire structure was underwater, with only a small cairn of stones about two metres across and a solitary upright iron bar breaking the surface. It is, by any measure, an easy thing to miss.

The structure is a crannog, a type of artificial or partly artificial island built in Irish and Scottish lakes, typically during the early medieval period, though some were constructed and reused across many centuries. They served as settlements, chosen for the natural defence the surrounding water provided. This particular example sits roughly 120 metres from the shoreline and was recorded on the 1912 Ordnance Survey six-inch map as a circular island about seven metres in diameter, named simply "Crannoge". When Christina Fredengren examined it during the Crannog Survey of County Sligo in 2000, she found the reality to be considerably larger than the old map suggested. Beneath and around the visible remnant lies a gently domed circular cairn of firmly packed angular stones, measuring approximately 18 metres across and rising between 1.4 and 1.8 metres above the lake bed. A scattering of flagstones, some up to half a metre across, was noted on the surface in the north-eastern section. The precise edges of the structure are indistinct, as often happens with submerged sites where lake sediment and time blur the boundaries.

What the 1912 map recorded as a small circular island is now almost entirely claimed by the lough, its outline visible only in the right light and at the right water level, if at all. The iron bar that marked its highest point at the time of the 2000 survey stands as an odd monument to something much older and considerably larger lying just out of sight below.