Corn Hill, also called Cairn Hill or Carn Clonhugh ( or ), is a hill in County Longford, Republic of Ireland. It lies north of Longford, between Drumlish and Ballinalee, in the parish of Killoe. At 278 metres above sea level, it is the highest hill in the county and has a television mast (Cairn Hill transmission site) on the top which rises 123 metres above the peak of the hill. Etymology The name Carn Clonhugh is an anglicization of the Irish Carn Clainne Aodha, meaning "cairn of Clann Aodha" (anglicised "Clanhugh"). Clanhugh was a historic territory in the northwest of County Longford. The earliest cartographic reference to the hill is found in the 1837–1842 Ordnance Survey Ireland 6 Inch map, which can be seen on the Ordnance Survey Ireland website. In cartography, the hill was referred to as Carn Clonhugh, but by the time of the 2nd edition 1887–1913 Ordnance Survey Ireland 25 Inch map, that was replaced with Corn (a corruption of Cairn) Hill. Today, it is known locally as Corn Hill. Sliabh Carbry Historic literature names this hill Sliabh Carbry after the pre-Norman kingdom of Cairpre Gabra. That a more ancient name of Sliabh Uillinn applied is supported by the Irish Annals. An old manuscript calls Sliabh Carbry the mountains of Uillim red-edged, the son of Fionn. Geology 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. Panorama The hill has extensive views of the landscape below. The forested land obstructs most of the view from Cairn A, but Cairn B has an extensive panorama from WSW to SSE. Sliabh Ban can clearly be seen from Cairn B along with the peat power-station of Lanesborough–Ballyleague and Ardagh Hill. Archaeology Passage graves usually cluster in two or more cairns, consisting of mainly a passage leading to a central chamber, corbelled roofed chamber sometimes in the form of a cruciform shape. The perimeter of the cairn would be edged by kerbstones, like those of Newgrange, Co. Meath and Carrowmore, Co. Sligo. Passage tombs are usually found in prominent locations, such as hill-tops. Generally speaking, the less complex the passage tomb is the older it is considered to be. The possible passage tombs atop Cairn hill are considered to be among the oldest in Ireland along with Carrowmore, Co.