It is overgrown now, easy to overlook, but the geometry beneath the vegetation is deliberate: an oval mound of stone, roughly 25 metres east to west and nearly 20 metres north to south, sitting almost 3 metres high above the lake surface. This is a crannog, an artificial or artificially modified island, a type of dwelling that was constructed across Ireland and Scotland from the Bronze Age through to the early modern period, built by communities who, for reasons of defence or status or simple practicality, chose to live out on the water rather than on dry land.

When a team from the Sligo Crannog Project visited the site in 2000, they recorded a structure of considerable complexity for something so quietly submerged in vegetation. At the centre of the main oval cairn, slightly offset to the east, sits a smaller concentration of loosely packed sandstones measuring roughly 7 metres by 6 metres, forming a kind of inner core. Around this inner mound spreads an uneven platform of stones, extending nearly 12 metres to the west and just over 11 metres to the north. Most intriguing is a feature running along the northern side of the site: a low, linear drystone-walled structure, about 5 metres long, just over a metre wide, and less than a metre high. The investigators suggested it may be the remains of a jetty, the point where a boat would have been tied up and people would have stepped ashore onto what was once someone's home.