The MacDonnells (Mac Domnaill) descend from Domhnall, son of Murtagh Mor O’Brien, High-King of Ireland, who died in 1119. They were hereditary bards to their O’Brien kinsmen. A branch of these Thomond MacDonnells settled in Connacht.

The MacMahons (Mac Mathghamhna) descend from Mahon, another son of Murtagh Mor O’Brien, mentioned above, who lived from 1094 to 1119. Their patrimony consisted of the territory comprising the present baronies of Moyarta and Clonderlaw in the southwest of County Clare. The famous Marshall of France, Patrick MacMahon, later president of the French Republic, was of these Clare MacMahons, being the grandson of John MacMahon, himself a French marquis (d’Eguilly).

The Ui Bloid were a branch of the Ui Toirdealbhaigh whose territory originally lay around the deanery of Omulled in the east of County Clare. Besides the O’Shanahans and O’Duracks, the Ui Bloid comprised the chiefly families of O’Aherne and O’Kennedy. The Ui Cearnaigh, of which the O’Ahernes (0 Eachtighearna) were the chief family, inhabited the territory around Six-mile-bridge until they were driven out about 1318 by the MacNamaras. Afterwards they are found chiefly in Limerick and Cork, but also in Waterford. The O’Kennedys (0 Cinnide) derive their descent from Cinneidigh, son of Donnchuan, brother of Brian Boru (see under O’Brien above). They were originally seated at Glenomra, where their territory was coextensive with the present parish of Killokennedy, in the east of County Clare. On being driven from that territory by the O’Briens and MacNamaras, they afterwards settled in north-central Tipperary, in the baronies of Upper and Lower Ormond, where they became numerous and far more powerful than they had ever been before. From the twelfth to sixteenth centuries they ranked as Lords of Ormond, and were divided into three great branches, 0 Ginneide Fionn (The Fair O’Kennedy), 0 Cinneide Donn (The Brown O’Kennedy) and 0 Ginneide Ruadh (The Red O’Kennedy). They are said by Keating to have considered themselves to be under the special protection of St. Ruadhan of Lorrha. A branch of the family settled in Antrim about 1600. The existence of the Glann Gearnaigh O’Kennedys of the Laiginian tribe of Ui Maine in Galway probably indicate the pre—Dalcassian origin of the collateral kinsmen of Brian Boru (see Chapter IX), and thus of the great Brian himself.

The MacGraths (Mag Raith) or MacGrays (Mac Raith) were hereditary poets and chroniclers to their O’Brien kinsmen, and spread with them into Tipperary and Waterford. They ran a bardic school at Cahir and the ruins of their castle in Waterford are still to be seen.

The O’Fogartys (0 Fogartaigh) were a Dalcassian sept in County Tipperary, and were formerly the chiefs of Eile Ui Fhogartaigh, now the barony of Elyogarty in east-central Tipperary.