It measures about twenty metres east to west and fifteen metres north to south, rising only a metre above the waterline. Around its edges, the rotting stumps of timber stakes break the surface intermittently, the remnants of a palisade that once defined the island's boundary. This is a crannog, an artificial or heavily modified island built up from earth, stone, and organic material, typically used as a defended dwelling place. The form is ancient in Ireland, with many crannogs dating back to the early medieval period, though this one tells a different story.

Radiocarbon dating carried out by the Discovery Programme, drawing on wood recovered from the site, returned a date of 320 plus or minus 20 BP, placing construction or use somewhere between AD 1429 and 1643. That range is significant. It situates this crannog not in the remote early medieval world most people associate with the type, but in a period of considerable upheaval in Connacht and Ulster, spanning the late Gaelic lordship era through to the early decades of English plantation. Research published by Kieran O'Conor and Christina Fredengren in 2019 has shed light on medieval settlement patterns across County Leitrim, and this site sits within that broader context of a landscape where defended island dwellings remained a practical choice well into the late medieval and early modern period. The silt causeway, which would have allowed access on foot while still providing a degree of separation from the surrounding land, is a feature that speaks to both the practicality and the vulnerability of life here.

The island is overgrown today, and the timber stakes are only intermittently visible depending on water levels and conditions. Drumlea Lough itself is a compact, subtriangular lake, roughly 400 metres from north to south and 370 metres east to west, with the crannog tucked into its south-eastern angle. The collapsed stakes in the shallows are easy to miss unless you are specifically looking for them.