The Conmhaicne or Conmaicne were an ancient tribal grouping that were divided into a number of distinct branches that were found scattered around Ireland in the early medieval period. They settled in Connacht, where they gave their name to several territories.
The word Conmacne means "progeny of Conmac" (ne, a progeny). Conmac itself means "hound-son" (con, hound; mac, son).
Known branches were:
- Conmaicne Mara (the Conmaicne of the sea) were located in what is now the extreme west of County Galway and gave their name to the territory they occupied i.e. Connemara, which is the anglicised form of Conmhaicne Mara.
- Conmaicne Cenéoil Dubáin, or Conmaicne Dúna Móir, at Dunmore, County Galway.
- Conmaicne Cúile Tolad, of Kilmaine, County Mayo (aka Conmaicne Meic Oirbsen Máir)
- Conmaicne Maigh Rein, or Conmaicne Rein na bFomorach, in south County Leitrim and into County Longford.
- Conmaicne Maenmaigh, also known as Conmaicne Críche Meic Erca, located around the former parish of Kilconickny, Loughrea. Kilconickny means "church of the Conmaicne".
- Conmaicne Sléibe Formaile, near Ballinlough, in west County Roscommon.
The Diocese of Ardagh was established in 1111 as the see for east Connacht. At the Synod of Kells-Mellifont its area was reduced to the territory of the Conmaicne with the kingdom of Breifne forming a new Diocese of Kells.
- Some Connacht Population-Groups, Nollaig Ó Muraíle, in Seanchas:Studies in Early and Medieval Archaeology, History and Literature in Honour of Francis John Byrne, pp. 176–76, Four Courts Press, Dublin, 2000
- Medieval Ireland: Territorial, Political and Economic Divisions, Paul Mac Cotter, Four Courts Press, 2008, pp. 134–135. ISBN 978-1-84682-098-4