Baoisgne	The clan of Finn, located in Laigin (Linster).
Beag	There are two candidates for this clan, Ó Beaglaoich & Ó Baoighealláin. The former comes from Co Donegal and has been anglicized to Begley, while the latter is from Co Fermanagh and now called Boylan.
Cenel Conaill	Rulers of Tir Conaill (Co Donegal) - Northern Ui Neill were divided into two main branches, Cenel Conaill and Cenel nEoghain. Cenel Conaill were the more powerful from the late sixth to the middle seventh century, with Flaithbertach mac Loingsig abdocating the overkingship of the Ui Neill in 734 A.D.
Cormac	The name Connemara comes from the tribe of Conmac, or Conmaicne, a warrior tribe which was sent to the area by the ancient Gaelic Kings of Connacht to ensure their hegemony. The branch of the tribe which went to the coastal area became known as Conmaicnemara, or 'the tribe of Cormac by the sea'.
CuChulainn	Family line of the great Ulster warrior of the same name, Dal Fiatach subkingdom of Ulaid at the Ulster king’s court of Eamhain Macha in the tribal lands of the Darini.
Cumhaill	In the line of Fionn’s father Cumhaill it is reckoned to originate from Co. Siligo at Ben Bulben the last stronghold of the Fionnia.
MacRoth	Named for Fergus, former king of Ulster & mentor of Cu. The same Gaelic surname is found in Scotland. There are two main septs in Ireland. One was located at Termon on the borders of Donegal and Fermanagh, its head being Corab of St. Daveog; the other in County Clare where the family supplied ollamhs in poetry or hereditary poets to the O'Briens of Thomond. The name can still found in Co. Clare, but the present day descendants are mostly in Co. Tipperary and Co. Waterford.
Manach	(manach- a monk) a minor sept of Corca Laoidhe in the south-west of Co. Cork; it is placed in the "Book of Lecan" and other medieval manuscripts in the O'Hennessy territory at the head of Ross Bay. The name was never numerous and is now scarce, being rarely found outside the counties of south-west Munster.
Morna	From the myth: Goll Mac Morna was leader of the Connaught branch of the Fianna, he had ousted Finn's father Cumhaill from power at the Battle of Cnucha now known as Castleknock in Dublin. Goll was part of the clan Morna who were rivals of the clan Baiscne in power struggles. Finn wrested the leadership of the Fianna back from Goll Mac Morna when he managed to kill the Sidhe prince Aillén Mac Midgna. Thereafter he was ordered by Cormac Mac Art to be on cordial terms towards Fionn and he promised the king that he would. There are many stories which show that Goll developed a respect for Finn against the wishes of the rest of the Clan Morna who still held a grudge. Fionn promised Goll his daughter Cainche's hand in marriage as reward for rescuing him from Conarán's daughters. Although he already had Scandlach for a wife. He had a disagreement with Finn's son Cairell and killed him in the Battle of the White Strand (Fionntraigh, Bantry Co. Cork), this action lead to his own death because he went into a cave to hide from the anger of Fionn and the Clan Baiscne and he was laid siege there and died of starvation and thirst after twelve days, despite his wife begging him to come out of the cave. Conan Maol his clansman swore to avenge his death on Fionn and this lead to the final split of the Fianna into various fractions and its downfall, and the end of the protective army of Ireland, which kept the invaders out. Nearest trace is the kingdom of Osraige (Ossory). The ancient Kingdom of the Osraige, an early Erainn tribe whose first king was Aengus Osrithe, flourished in the second century of the Christian era. In the fifth century the neighbouring tribe of the Deisi, aided by the Corca Laighde, conquered South Ossory, and for over a century, the Corca Laighde chiefs ruled in place of the dispossessed Ossory chiefs. Early in the seventh century the ancient chiefs recovered much of their lost possessions, the foreigners were overcome, and the descendants of Aengus ruled once more. One of the greatest was Carroll, prominent in the ninth century and distinguished in the Danish wars. Kilkenny County forms much of what was known as the kingdom of Ossory. Once concitered a part of Mumu (Munster) it became a part of Linster in 1912.
Niafer	Co Meath or the kingdom of Berga the Nia Fer are styled as the guardians of the high-king of Tara. Cairpre Nia Fer was the son of Ross of Leinster, brother of Ailill who married Medb and was King of Connaught, and brother of Find who was King of Leinster. Cairpre was ruler of Tara and was therefore a high-king over the rest of Leinster and Míde (which was a fifth province in those days and corresponds to the northern part of Leinster today
Niall	The Southern Ui Neill of Berga were divided into two major rival branches, the Sil nAeda Slaine and Clann Cholmain, and they dominated the lands of Meath, Westmeath and other parts of surrounding counties. The Sil nAeda Slaine were very powerful in the seventh century. The annals record the slaying of Finsnechta Fledach macDunchada, king of the Sil nAedo Slane, by his rivals the Fir Chul of the Luigne of Brega (Tara). Clann Cholmain managed to take the overlordship of the Ui Neill in 743. In the mid-ninth century their king claimed to be king of Ireland.
Ui Maine	Another powerful federation of tribes was the Ui Maine whose extensive territory embraced large areas of what is now south Roscommon, Galway and north Clare. The Ui Maine were pre-Milesian Celts who were later given a fictitious Milesian pedigree showing them descended from Maine Mor, son of Eochu, etc. Notwithstanding their importance, O'Rahilly points out that they were vassals who paid tribute to the Milesian kings of Connacht. Among the Ui Maine dwelt the Sogain, a Cruthin (Pict) tribe, and the Dal naDruithne believed to be Tuatha De Danann Celts. It is worth mentioning that this is also a Sept of the Southern Ui Nialls