An enclosure, in the broadest sense, is exactly what it sounds like: a defined area bounded by a bank, ditch, wall, or some combination of these, raised by human hands for purposes that varied enormously across the centuries. Some enclosed settlements, some enclosed ritual spaces, some enclosed farmland or livestock. Without excavation or detailed survey, the precise character and date of any given example tends to remain open. Doonmacreena's enclosure is one such site, recognised as a monument but not yet fully documented in any publicly available form.

The place-name itself offers a small clue. "Doon" derives from the Irish "dún", meaning a fort or fortified place, a word that appears across Mayo and the wider west of Ireland wherever early medieval or prehistoric earthworks once defined the landscape. Whether the enclosure here is the feature that gave the townland its name, or whether the name and the monument have separate origins, is the kind of question that field survey and closer scrutiny of the earthwork's form might eventually answer. For now, Doonmacreena occupies a quiet corner of Mayo's layered prehistoric and early medieval geography, its enclosure noted but its story still largely untold.