Sliabh an Iarainn – “Sliabh Comaicne”

Sliabh an Iarainn (“mountain of the iron”, historically corrupted as “Slieve Anierin”) is a large hill in County Leitrim, Ireland, its shape evolving to its present form by ice age glaciers moving southwest over millions of years, the Morainic drift heaping thousands of drumlins in the surrounding lowlands. Irish cultural folklore records strong association with the mythological “Tuatha De Dannan”. Sliabh an Iarainn is an important natural heritage site with exposed marine and coastal fauna of paleontological interest

The name Irish: Sliabh an Iarainn, meaning “mountain or moor of the Iron'”, originates from an appreciation Iron ore deposits are present. Boate (1652) said “the mountains are so full of this metal, that hereof it hath got in Irish the name of Slew Neren, that is, Mountains of Iron“. Historically, Sliabh an Iarainn was called “Sliabh Comaicne“, the mountain of Conmaicne Rein in Connacht. The Irish name spelling is commonly used, though pronounced and sometimes corrupted as “Slieve-An-Ierin”.


Sliabh an Iarainn is an important natural heritage site due to unbroken sequence of Carboniferous marine fossils present in the rock layers spanning the Namurian (326-315 million years ago) and lower Westphalian (313-304 million years ago) stages of the Silesian (series). The Geological survey of Ireland (1878) wrote “the Geologist may examine all the formations of the district from the Lower Silurian up to the outlier of Coal-measures that crowns Slieve-an-Ierin… It is a rare thing in most countries to find so much comprised in so small a space”.

Sliabh an Iarainn is an imposing “mountain” or Marilyn, the highest in county Leitrim, rising from the eastern shore of Lough Allen to a summit elevation of 586-metre (1,923 ft), towering over and dominating the rugged landscapeOn this summit at 520 metres (1,706.0 ft), a Triangulation station of the Ordnance Survey is fixed on a low concrete plinth.

Tuatha De Dannan

The Book of Invasions describes the Tuatha Dé Danann, tribe of the goddess Danu” arriving in Mesolithic Ireland through the air before landing their floating-ships on the summit of Sliabh an Iarainn, “the mountain of Conmaicne Rein in Connacht“. The men included Nuada the king, Manannan the powerful, Neit the battle god, and Goibniu the Smith. The women included Badb the battle goddess, Eadon the poets nurse, Brigit a goddess, and Dagna the goddess mother. Messengers informed Eochaid son of Ere, and king of the Fir Bolg, that a new race of people had settled in Ireland. The Firbolgs sent forward their champion Sreng and the Tuatha De Danann getting sight of his approach sent their champion Bres. The two champions had a meeting at Magh Rein below Sliabh an Iarainn but no peace was concluded. The Tuatha Dé Danann defeated the Firbolg at Battle of Moytura. Three centuries later the De Danann retreated to the Celtic Otherworld on being displaced by the Milesians, mythological ancestors of the Irish race.

Some fringe historians suggest a passage in the Book of Invasions concerning the appearance of the Tuatha Dé Danann in Ireland, records “the arrival of aliens in spacecraft with cloaking devices” at Sliabh an Iarainn.

Gobán Saor

Metal workers were held in high esteem, and the Irish Pantheon Gobán Saor is synonymous with the legendary Scandinavian named Vaeland Smith and Goibniu of the Tuatha De Dannan. According to oral tradition, Gobán Saor (“Goibhenen”), Tuatha De Danann metalsmith, worked the mines here.

Hunger stone

Long ago in the parish of Kiltubrid the term Irish: fear gorta (“hungry man”) was applied to a hunger which supposedly may inflict a person on the mountains, proving fatal if not quickly satisfied. This hunger immediately affected any person who walked on a legendary “fear-gorta stone” at the base of Sliabh an Iarainn.

Fairies revenge

Oral tradition in Cavan described how a local man, “Turlough the Yellow-haired”, asked the mountain fairies to destroy the Swanlinbar Iron works and send the foreigners away, and “the flood came rushing down from the mountain, from Binn Eachlainn, and it left neither mill nor wig nor man behind but swept them all down to Lough Erne“.

AUTHOR’S NOTE: The Kingdom of Breifne or Bréifne ([ˈbrʲeːfnʲe]; anglicized BreffniBreffnyBrefnieBrenny) was a confederation of Irish túaitheheaded by a ruirí drawn from the Uí Briúin Bréifne. The Bréifne territory included current day Irish counties of Leitrim and Cavan, along with parts of County Sligo (an area roughly equivalent to the modern Roman Catholic Diocese of Kilmore). The Ó Ruairc kings (O’Rourke) maintained lordship over West Bréifne (mainly County Leitrim), while the Ó Raghallaigh kings (O’Reilly) retained lordship over East Bréifne (County Cavan). The Kingdom of Bréifne region was part of the kingdom of Connachtup until the time of Queen Elizabeth I. In that time it was shired into the modern counties Cavan and Leitrim, Leitrim remaining a part of the province of Connacht while Cavan became part of Ulster.

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