Portal tombs, sometimes called dolmens, consist of two or more tall upright stones flanking an entrance, capped by a large covering stone that often tilts dramatically upward at the front, giving the whole structure the appearance of a table propped at an angle. They were built during the Neolithic period, roughly five to six thousand years ago, and served as collective burial monuments, though their full ritual significance remains a matter of ongoing debate among archaeologists.

The principal scholarly record for this site comes from the survey carried out by Ruaidhrí de Valera and Seán Ó Nualláin, published in 1964 as part of their systematic county-by-county documentation of megalithic tombs across Ireland. Volume II covered County Mayo, a county that contains a remarkable concentration of prehistoric monuments. The place name Cnoc na Lobhar is itself worth pausing on. Associations between elevated ground and lepers, or more broadly with outsiders and the margins of medieval society, appear occasionally in Irish topography, though whether this name preserves any genuine historical memory or arrived through other means is not easily determined from the name alone.