Historic literature names this hill Sliabh Carbry after the pre-Norman kingdom of Cairpre Gabra.

[3] Cairn Hill is located in area of north Longford dominated by Middle to Upper Ordovician slate, sandstone, conglomerate, and greywacke according to the Geological Survey of Ireland public data viewer.

The possible passage tombs atop Cairn hill are considered to be among the oldest in Ireland along with Carrowmore, County Sligo.

The first refers to the location of the burial place of Queen Maeve's nephew and murderer, Furbaide Ferbend on the summit of Sliabh Uillen (Cairn Hill).

One of the cairn on Sliabh Carbry (in Cairpre Gabra) was indeed anciently called "Carn Furbaidhe".

[6] The second legend refers to Cairn A (or Carn Caille)and its creation by the Cailleach a Bheara or ancient Hag/Witch who dropped stones out of her apron as she flew over the hill.