A cairn, in its simplest form, is a deliberate accumulation of stones raised by human hands, most often over a burial or as a territorial or ceremonial marker. They range from modest field-clearance heaps to elaborate megalithic constructions covering chambered tombs, and distinguishing between them often requires excavation or careful survey work. The one at An Doirín is recorded as a monument, which places it in at least provisional company with the genuinely ancient, but beyond that the record is, for now, largely silent.

The place name An Doirín is Irish for something close to "the little oak grove" or "the small thicket", a diminutive suggesting a modest but distinct feature in the local landscape. Mayo is thickly scattered with prehistoric monuments, many of them concentrated along its Atlantic coastline and across the broad boglands that have preserved so much. Cairns in this region have sometimes yielded Bronze Age or Neolithic material when investigated, though many remain unexcavated and undated. Without further detail on this particular site, it sits in that category of monuments that are known to exist, are considered worth protecting, and are otherwise waiting for the closer attention they have not yet received.