The Conmhaícne (descendants of Con Mhac) 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 take their name from a mythical ancestor known as Con Mhac "hound son".
The Conmhaícne Mara (the Conmhaicne 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. The territory of Conmhaicne Mara / Connemara covers all of the barony of Ballynahinch and the civil parish of Inishbofin, which is in the barony of Murrisk. The territory contains the five civil parishes of Ballynakill/Baile na Cille, Ballindoon, Moyrus/Maigh Iorras, Omey/Iomaidh Fheicín and Inishbofin/Inis Bó Fine. The territory contains the five Catholic parishes of An Clochán (Clifden, Omey & Ballindoon), Iorras Ainbhtheach (Carna), Cloch na Rón/(Roundstone), Baile na Cille (Ballynakill) and Inis Bó Fine/(*Inishbofin (County Galway)).
The area of County Galway in which Connemara lies is known as Iar Connacht i.e. the portion of County Galway west of Lough Corrib and a small piece of County Mayo.
Other branches of the Conmaicne located in what is now County Galway included the Conmaícne Cenéoil Dubáin (also known as Conmaicne Dúna Móir) and the Conmaícne Cúile Taland. The parish of Kilconickny, which means "church of the Conmaicne"is located west of the town of Loughrea.
The chiefs of the Conmaicne Mara were the O’Kealys, and their cadets were the MacConneelys, O’Devaneys, and O’Clohertys, with the O’Falons [Folan] as their hereditary brehons. O’Kealys, relocated to Ui Oirbsen, but they were to find themselves imposed upon again after just a few decades. The MacConneelys stayed in their home at Ballyconneely Peninsula, but soon found themselves neighbors of the O’Flahertys.