Scattered across the Irish landscape in their hundreds, cairns range from modest field clearances to elaborate Neolithic burial monuments, and distinguishing one type from another often requires more than a passing glance. The cairn recorded at An Geata Mór in County Mayo sits within a county that is unusually rich in such prehistoric stonework, from the great passage tombs of the Céide Fields area to the humbler accumulations left by generations of farmers clearing ground.

An Geata Mór, meaning roughly "the great gate" in Irish, is a townland in Mayo, a county whose boglands have preserved archaeological features that would have vanished long ago in more intensively cultivated regions. Cairns in this part of Connacht can date anywhere from the Neolithic period, several thousand years before the common era, through to the early medieval and even post-medieval periods, when cairns were still used as boundary markers or memorial stones. Without more detailed field information it is not possible to say with certainty which tradition this particular example belongs to, nor what its original purpose was, though its formal recognition as a monument suggests it is considered of archaeological significance rather than a product of routine land clearance.