A crannog, the term for an artificial or artificially enlarged lake dwelling constructed throughout Ireland and Scotland from the Bronze Age well into the early medieval period, once sat at the centre of this small lake near Cluain Bú. It is now submerged, swallowed by a gradual rise in water level that has erased it from view entirely, leaving only the cartographic evidence of what was once visible.

The site was recorded on the third edition of the Ordnance Survey six-inch map, published in 1934, where it appears as a small circular island roughly twenty metres in diameter. That modest footprint is typical of crannogs, which were generally compact, timber-built platforms or stacked-stone islands offering their inhabitants security through the simple logic of water as a barrier. By the time archaeological inventory work was compiled for North Galway in the late twentieth century, the site had already been lost to view beneath the lough. A second possible lake dwelling has also been identified approximately one hundred metres to the south-west, which raises the intriguing possibility that this quiet stretch of water once supported more than one such settlement, though neither can now be examined without considerable effort.