Roughly ten metres across, it sits quietly in aerial photographs going back to 1995, yet no cartographer has ever marked it, and no researcher has yet set foot on it. The suspicion is that it is a crannog, an artificial or partly artificial island, typically built up from timber, stone, peat, and brushwood, that served as a defended homestead during the early medieval period and sometimes well beyond. Ireland has thousands of them, many still unrecorded, and this appears to be one.

The site was first identified by Anne-Karoline Distel, who noticed the island feature in aerial imagery. Garty Lough itself is a subrectangular lake stretching roughly 1.23 kilometres from east-northeast to west-southwest, with a width varying between about half a kilometre and just under a kilometre. The bay in which the possible crannog sits measures approximately 90 metres east to west and 50 metres north to south, making it a sheltered, relatively enclosed corner of the lough. The absence of the island from any mapped source is itself unusual; even tentative or doubtful features tend to attract at least a note on Ordnance Survey revisions. Its omission here likely reflects how easy it is for a small, overgrown islet to escape notice at ground level, particularly in a bay set back from the main body of a lake.