The island, measuring roughly 36 metres across its interior, is encircled by the remains of a stone wall that still rises 1.3 metres above the current water level. This substantial wall, 2.6 metres thick, would have formed a formidable defensive barrier when the water levels were different and the structure fully functional.

The site represents what archaeologists classify as a ringfort or cashel, a type of fortified settlement common throughout Ireland during the early medieval period. These structures typically served as defended homesteads for farming families, offering protection for both people and livestock. The presence of an entrance gap on the southern side, also measuring 2.6 metres wide, indicates this was indeed a deliberately constructed dwelling place rather than a natural formation.

What makes this particular site intriguing is its current state of partial submersion, which raises questions about changing water levels in Lough Anna over the centuries. Whether the island was always surrounded by water, making it a crannog (an artificial island dwelling), or whether rising water levels have since claimed what was once a lakeside or promontory fort, remains a matter for archaeological interpretation. The site was documented as part of the comprehensive Archaeological Survey of County Donegal, compiled by Brian Lacey and his team in 1983, which catalogued field antiquities from the Mesolithic period through to the 17th century.