More than a hundred cartloads were carted away and sold, and for years afterwards, during the worst of the Famine, the poor of the nearby town of Bruff waded out at low water to collect whatever remained, selling the fragments to bone dealers for whatever they could get. The island at the centre of this, Garrett Island, is a crannog, a type of artificial or semi-artificial island settlement built up from timber, stone, and debris, used across Ireland and Scotland from the Bronze Age well into the medieval period as a defensible place to live. What makes the Lough Gur example unusual is not just its archaeological complexity but the peculiar documentary trace left by what the draining uncovered.

Professor Harkness, writing in 1869, catalogued the bone assemblage in considerable detail. The animal remains were largely from Bos longifrons, a small breed of domestic ox, whose skulls bore fractures consistent with the blow that killed them; pig, goat, stag, and dog bones were also recovered. The dogs were of particular interest to Harkness, who identified them as likely ancestors of the rough-haired Irish greyhound, a breed now extinct, distinguished by a long muzzle and large frame. A small number of human remains, notably lower jawbones of notably heavy build, were mixed in with the rest. The island itself had changed considerably by the time Harkness was writing. The 1840 Ordnance Survey six-inch map shows a modest oval, roughly 40 metres by 31 metres, sitting about one and a half metres above the waterline. By the 1897 edition, following the lowering of the lake level by around three metres, the mapped island had grown to roughly 190 metres by 100 metres. The site also carries a historical association: it has been tentatively identified as the island of Loch Gair said to have been built by Brian Boru, the early medieval High King of Ireland, though this attribution is not certain.

Garrett Island sits about 45 metres west of Knockadoon Peninsula, the narrow arm of land that juts into Lough Gur on its eastern side, and a causeway once connected the two. Modern aerial imagery shows the island as a wood-covered mass, roughly 250 metres north to south, with shallow reefs visible in the surrounding water. The lake and its immediate surrounds are accessible from the Lough Gur visitor centre nearby, and views across to the island can be had from the peninsula itself. The island is not, as far as the records indicate, open to casual visitors, but the proximity of the shore and the clarity of the shallow water mean the reefs and the general form of the site are legible from the bank, particularly when water levels are low.