The monument at Ros Dumhach, on the remote Erris peninsula in north-west Mayo, is not a druidic ritual site but a megalithic tomb, a prehistoric stone structure whose true origins reach back thousands of years before the Iron Age figures that popular imagination tends to attach to such places. The disconnect between the name and the archaeology is itself a small lesson in how communities have long tried to make sense of the massive, enigmatic stonework they inherited from much earlier inhabitants of the Irish landscape.

The site is documented in Ruaidhrí de Valera and Seán Ó Nualláin's Survey of the Megalithic Tombs of Ireland, Volume II, which covered County Mayo and was published by the Stationery Office in Dublin in 1964. That survey remains a foundational work for understanding the distribution and typology of megalithic monuments across the island, cataloguing the chambered cairns, court tombs, portal tombs, and wedge tombs that were erected during the Neolithic and into the early Bronze Age. Ros Dumhach sits in a part of Mayo that, despite its apparent isolation today, preserves a notable concentration of prehistoric remains, a reminder that the boggy, wind-scoured landscape of Erris was once rather more hospitable and more densely settled than it has been in recent centuries. The monument carries the designation of national monument number 386 and is in state care, which affords it a degree of legal protection.