Crom Cruach (Old Irish: Cromm Crúaich [ˈkɾˠɔmˠ ˈkɾˠuəç]) was a pagan god of pre-Christian Ireland. According to Christian writers, he was propitiated with human sacrifice and his worship was ended by Saint Patrick.
He is also referred to as Crom Cróich, Cenn Cruach/Cróich ([ˈkʲɛnˠː ˈkɾˠuəx]) and Cenncroithi ([ˈkʲɛnˠː ˈkɾˠɔθʲɨ]). He is related to the later mythological and folkloric figure Crom Dubh. The festival for Crom Cruach is called Domhnach Chrom Dubh, Crom Dubh Sunday.
The references in the dinsenchas ("place-lore") poem in the 12th century to sacrifice in exchange for milk and grain suggest that Crom had a function as fertility god. The description of his image as a gold figure surrounded by twelve stone or bronze figures has been interpreted by some as representing the sun surrounded by the signs of the zodiac, suggesting a function as solar deity.
Crom Cruach's name takes several forms and can be interpreted in several ways. Crom (or cromm) means "bent, crooked, stooped". Cenn means "head", and by extension "head, chief". Cruach (or crúach) is a noun meaning "pile, heap, mound, stack", generally of grain, hay, peat or other gathered goods, booty, and so on, including slaughtered fighters. A common extension is its reference to hills or mountains that look like stacks or piles.
According to an Irish dinsenchas ("place-lore") poem in the 12th century Book of Leinster, Crom Cruach's cult image, consisting of a gold figure surrounded by twelve stone figures, stood on Magh Slécht ("the plain of prostration") in County Cavan, and was propitiated with first-born sacrifice in exchange for good yields of milk and grain. Crom Cruach is described as a wizened god, hidden by mists, and is said to have been worshipped since the time of Érimón. An early High King, Tigernmas, along with three quarters of his army, is said to have died while worshipping Crom on Samhain eve, but worship continued until the cult image was destroyed by St. Patrick with a sledgehammer.
This incident figures prominently in medieval legends about St. Patrick, although it does not appear in his own writings, nor in the two 7th century biographies by Muirchu and Tírechán. However J.B. Bury, ('The Itinerary of Patrick in Connaught, According to Tírechán', Proceedings of the Royal Irish Academy: Archaeology, Culture, History, Literature, Vol. 24, 1902 - 1904, page 156), infers that there is a missing passage in Tírechán about Crom Cruaich and Ludwig Bieler is non-committal on the point.
In the 9th century Tripartite Life of Saint Patrick the deity is called Cenn Cruach, and his cult image consists of a central figure covered with gold and silver, surrounded by twelve bronze figures. When Patrick approaches it he raises his crozier, the central figure falls face-down, with the imprint of the crozier left in it, and the surrounding figures sink into the earth. The "demon" who inhabits the image appears, but Patrick curses him and casts him to hell. Jocelin's 12th century Life and Acts of St. Patrick tells much the same story. Here the god is called Cenncroithi, interpreted as "the head of all gods", and when his image falls the silver and gold covering it crumble to dust, with the imprint of the crozier left on bare stone.
A decorated stone known as the Killycluggin Stone (from Irish: Coill an Chlogáin meaning 'the Wood of the Bell-Shaped Stone') has been interpreted by some as the cult image of Crom Cruach. It was found at Killycluggin, County Cavan. It was discovered broken in several pieces and partly buried close to a Bronze Age stone circle, inside which it probably once stood.
The 14th century Book of McGovern, written in Magh Slécht, contains a poem which states that Crom was situated at Kilnavert beside the road and that the local women used to tremble in fear as they passed by. There is still a local tradition in the area that the Killycluggin Stone is the Crom stone.
There is another standing stone identified with Crom Crúaich in Drumcoo townland, County Fermanagh. It has the figure of a man walking engraved on it, which either represents Saint Patrick or a druid, depending on when it was engraved. A nearby street is named Crom Crúaich Way after it.
-  'The Irish God "Crom Crúaich of Magh Slécht" : a review of the sources'
- "Celtic Gods, Crom Cruaich". Magic of Mythology. Archived from the original on 4 July 2010. Retrieved 9 December 2010.
- Dictionary of the Irish Language Based on Old and Middle Irish Materials, Dublin, 1990
- E. Gwynn (ed & trans), The Metrical Dindshenchas Vol. 4 poem 7; see also Annals of the Four Masters M3656; Geoffrey Keating, History of Ireland 2.25
- Ludwig Bieler (ed. & trans.), The Patrician Texts in the Book of Armagh, Dublin Institute for Advanced Studies, 1979
- James O'Leary (ed & trans), "Tripartite Life" Part II, The Most Ancient Lives of St. Patrick, 1880
- James O'Leary (ed & trans), "The Life and Acts of St. Patrick by Jocelin" Chapter 56, The Most Ancient Lives of St. Patrick, 1880
- Killinagh Church and Crom Cruaich by Oliver Davies and D. Lowry-Corry, in Ulster Journal of Archaeology, Third Series, Vol. 2 (1939), pp. 98-104