Historically and in Irish law from ancient times, Ireland was divided between five kingdoms, or provinces, each with its own king: Midhe (Meath), Connacht, Ulaidh (Ulster), Laighin (Leinster), and Mumhan (Munster). Over the five was the nominal High King at Tara in the heart of Meath, but his authority was mostly ceremonial. Often, the High King was also king of one of the provinces, such as when the O’Briens and O’Connors held the office. Below each provincial king were a number of overkings over several tuatha, the basic unit of life in Ireland, each of which had its own king (ri in Irish).
According to legend, Conn Cetchathach, progenitor of the Connachta, lost the Battle of Maigh Nuadad to Eoghan Mor, progenitor of the Eoghanachta, in the 2nd century, and was forced to accept division of the island between them. Leth Cuinn, or Conn’s Half, included Connacht, Ulaidh, and Midhe while Leth Moga, or Mugh’s Half (Eoghan was also known as Mug Nuadat) took in Mumhan and Laighin. It’s a colorful story that reflect the political realites of the later Middle Ages than actual history.
Geographically and geologically, however, the division is nearly exactly the same. The two halves of Ireland along approximately the same lines come from different prehistoric continents that crashed together and formed the island (and its next-door neighbor, Britain) around 425 megaanni ago (roughly 425,000,000 BCE). The continent of Laurentia, now the greater part of North America, contributed the north while the micro-continent of Avalonia contributed the southern half.
The Laurentian craton that forms the north half of the islands of Ireland and Britain and the eastern two-thirds of North America is the oldest landmass to remain above the sea, first rising around 612,000,000 BCE. That’s why Southern Appalachia where I live has the most diverse and most number of species of fauna and flora on the planet. Lots more things to be allergic to.
In earliest recorded history, the kingdom, or province (coiced, i.e. “fifth”) from the perspective of Ireland as a whole, of Connacht was known as Ol nEchmacht, after the then dominant group of dynasties, of which there were three: the leading sept, the Gamanraige, ruling from the River Galway to the rivers Duff and Drowes from the famous citadel at Cruachan, the Fir Craibe to the south of them, and the Tuatha Taiden in roughly the later Ui Maine.
It seems the western districts beyond the line of the River Galway, at least the southern part of that region, were left to their own devices, much as was the case in the medieval through early modern times, though by Irish law, the peoples who lived there—the Delbhna Tir Da Locha (in the barony of Moycullen), the Conmaicne Mara (in the barony of Ballynahinch), the Ui Oirbsen branch of the Partraige an-t Sleibh (in the barony of Ross)—were supposed to pay tribute to and receive stipends from the king of all Connacht at Cruachan.
The Fir Ol nEchmachta ruled the western province until the 5th century rise of the Connachta, descended from Conn Cetchathach (“of the Hundred Battles”), High King of Ireland in the 2nd century. The Connachta divided into four branches, one of which became the Ui Neill of western Ulster (the kingdom of the Ulaidh remained, but was reduced to modern Cos. Antrim and Down) and Midhe with the remaining three, Ui Briuin, Ui Fiacrach, and Ui Ailello, giving their collective name to the province.
The ascension of the three Connachta (“Teora Connachta”) and the Ui Neill coincided with the rise of the Eoghanachta over Mumhan, displacing the Corcu Loigde, and of the rival related dynasties of Ui Dunlainge (who became the O’Tooles) and of Ui Ceinnselaig (who became the MacMurroughs) in Leinster. The southern Ui Neill conquered the province of Midhe entirely while their northern cousins founded the kingdom of Aileach in what was once western Ulaidh. The Airghialla had already carved out their kingdom from Ulster in the 4th century, and their cousins the Ui Maine went on to conquer part of Connacht.
At one time, the kingdom of Connacht was the biggest province in Ireland in terms of both land and population, including Co. Cavan, Co. Longford, and Co. Clare in addition to Cos. Mayo, Sligo, Leitrim, Roscommon, and Galway. Co. Clare is both geographically and geologically part of Connacht, as it was politically until the separation of a branch of the Deisi Mumahn to become the Deisi Tuisceart after moving north into the south of Connacht sometime between the 500’s and 800’s, and making it Tuadh Mumhan (Thomond) in the 10th century.
The Deisi Tuisceart later became the Dal gCais, bitter rivals of the Eoghanachta for supremacy in Mumhan during the Middle Ages until the English Conquest in 1172. Their chiefs became the O’Briens, of whom the most famous is Brien Borumha. In return, their territory in the Aran Islands became part of Connacht (by conquest) in 1582. Co. Clare was made part of Connaught when counties were created but returned to Munster in 1639.
Poets and some of the laws continued with the practice of dividing Connacht into three, at first among each of the Connachta tribes, the Ui Briuin, Ui Fiachrach, and Ui Ailello, with the last two replaced in later times by the Ui Briuin Breifne and Ui Maine respectively, with the former taking their territory and the latter their place of prominence, at least among the poets and bards, such as John O’Dugan in his famous 14th century topographic poem.
Geographic divisions of Connacht
Teora (Tripartite) Connacht, the leading sept of which were the Ui Briuin Ai, later known as the Sil Murray, who eventually became the O’Connors. They were also (usually) kings of all Connacht, ruling from Cruachan until the 12th century when the king then moved his seat to Tuam. The name of the kingdom refers to the three dynasties and implies the statement in the first sentence. It was roughly coextensive with modern County Roscommon.
Iar (West) Connacht, the leading sept of which were the Ui Briuin Seola, later known as the Muintir Murchada, and finally as the O’Flahertys. The O’Flahertys directly ruled over Moyseola and dominated the tuatha to the immediate north (Conmaicne Cuile Toland) and south (Clan Fearghaill). At its height, Iar Connacht included Muintir Murchada in Maigh Seola and Ui Briuin Ratha to the east (together the modern barony of Clare) Clan Fearghaill (Dunkellin), Clan Cosgraig (south of Clan Fearghaill), Delbhna Tir Da Locha (Moycullen), Conmaicne Mara (Ballynahinch), and Ui Orbsen (later Joyce Country, now Ross). Geographically, though never politically, it also included Tir Umhall.
Until 1118, Iar Connacht included Conmaicne Cuile Tolad (Kilmain, Co. Roscommon), when the O’Flahertys lost it to Turlogh Mor O’Connor. After 1582 it took in Aran when the O’Flahertys ejected the MacTeige O’Briens. The authority of the O’Flahertys over the area west of River Galway (Tir Da Locha, Connemara, Joyce Country) was only nominal at best until the mid-13th century, when, of course, they no longer had their territories east of the river.
In terms of geography, West Connacht is confined to the region west of the River Galway; those territories to the east of the River Galway belong geographically to Upper Connacht.
Uachtar (Upper) Connacht, the leading sept of which were the Ui Maine, who were later the O’Kellys. The territory, actually in the south of Connacht, took in Co. Galway minus Iar Connacht and Deisceart Connacht, southern Co. Roscommon, and part of Co. Clare.
Iochtar (Lower) Connacht, the leading sept of which were the Ui Aillelo, who eventually died out or at least had their territories taken by a branch of the Ui Fiachrach Muaidhe later known as the MacDermotts, who in turn lost it to the Burkes after the Anglo-Norman invasion of 1172. In the 14th century, a sept of the O’Connors of Sil Murray took it from the Burkes. Lower Connacht is actually in the north, taking in Co. Sligo and part of Co. Mayo.
Deisceart (South) Connacht, the leading sept of which were the Ui Fiachrach Aidhne, who became the Cenel Guaire, then the O’Clerys. The territory took in southern Co. Galway and included the land from there down to the River Shannon until sometime between the 5th and 8th centuries, when the latter was lost to group seceding from the Deisi Mumhan who crossed the river and took what is now Co. Clare, becoming the Deisi Tuaisceart, later known as the Dal gCais, and later renaming the territory Tuadh Mumhan, or Thomond.
Airthir (Eastern) Connacht, the leading sept of which were Ui Briuin Breifne, who became the O’Rourkes. The territory took in modern Cos. Leitrim and Cavan. The O’Rourkes in the west divided their kingdom with the O’Reillys in the east.
Tuisceart (North) Connacht, the leading sept of which were the Ui Fiachrach Muaide, who later became the O’Dowds. The territory is actually in the northwest of Connacht, and took in most of Co. Mayo, including the Tir Umhall territory of the O’Malleys who were autonomous.
In practice, matters were much more complex and several tuatha were virtually independent of any outside interference.
Free tribes of the kingdom of Connacht
Now let’s take a look at political Connacht.
The Book of Rights and Privileges of the kings in Ireland, originally composed in the 5th century by St. Benin and updated (somewhat though not entirely) as necessary, gives the following as the free, non-tribute paying tribes of Connacht, termed Saortuatha, in the 11th century:
1. Sil Murray, also known as Ui Briuin Ai, who were the high kings of all Connacht from Cruachan (Rathconrath in Co. Roscommon); their tuatha was called Teora Connacht, roughly the equivalent of modern Co. Roscommon. The leading sept were the O’Connors.
Sil Cathail of the Ui Briuin Ai, whose leading sept were the O’Flannagans, alternated as high kings of Connacht with the Sil Murray throughout the 8th century, but never after. Their territory later became the barony of Roscommon in the county of the same name.
2. Ui Briuin, which had three main branches:
Ui Briuin Breifne, the two leading septs of which were the O’Rourkes. kings of all Breifne covering Cos. Leitrim and Cavan, and their cadets, the O’Reillys, kings of Muintir Maoilmhordha, equivalent to modern Co. Cavan that became East Breifne after an English-fomented fratricidal disagreement in 1256.
Ui Briuin Seola in Iar Connacht, the leading sept of which were the O’Flahertys, whose tuatha was later called Muintir Murchada. See Iar Connacht above.
Ui Briuin Ratha, the leading sept of which were the O’Dalys, held 14 townlands east of the Ui Briuin in Maigh Seola in Iar Connacht. The O’Canavans, physicians to Muintir Murchada, were a sept of this tribe.
The O’Malleys later called themselves the Ui Briuin Mhaille and the Corco Achlan later called themselves the Ui Briuin Sinn, but neither of these claims have any credibility.
3. Ui Fiachrach, once the kings of all Connacht, which had three branches:
Ui Fiachrach Muaidhe in Tuisceart Connacht, whose leading sept were the O’Dowds, the fleet admirals of Connacht, whose home tuatha was Tir Amalgaidh, or Tirawley. Their territory took in Co. Sligo, after they conquered the Ui Aillelo, and most of Co. Mayo.
Ui Fiachrach Aidne in Deisceart Connacht, whose leading sept were the O’Clerys. The territory occupied southern Co. Galway.
Ui Fiachrach Finn, a much smaller group that was never as influential as the others, lived in Maenmoy in what is now central Co. Galway, the modern barony of Loughrea. Their kingdom was conquered early on by the Ui Maine. Its rulers were the O’Mullulys and MacNaughtons.
4. Cenel Aeda na hEchtge, who were a branch of the Ui Fiachrach Aidne in the modern barony of Kiltartan in Co. Galway, formerly called Kinelea. Its two leading septs were the O’Shaugnessys and the O’Cahills. By the time of the English conquest, they had deposed their cousins of Ui Fiachrach from the rule of Aidne.
Each of these dominated a number of non-free, tribute paying tribes in their respective territories.
Free but tribute-paying tribes of Connacht
The kingdom of Connacht also had a number of tribes free of outside interference provided they paid tribute to Cruachan. These are the Fortuatha of Connacht, which had rulers of their own, not from an outside dominant tribe. The Book of Rights and Privileges lists the following as paying the annual tribute:
1. Ui Maine, whose leading sept were the O’Kellys. They were a free tribe not required to pay tribute for the freedom of their territory but had to pay the tribute of the non-free tribes they conquered. A branch of the dynasty that carved Airghialla out of Ulster, they migrated to Connacht and were permitted by Duach Galach, the third Christian king of Connacht, to conquer the Firbolg tribes of Magh Seincheinol. Later they also conquered the Delbhna Nuadat and the Ui Fiacrach Finn. The territory corresponds to what is now the baronies of Tiaquin, Kilconnell, and Killain in eastern co. Galway and Athlone and Athcarnan in southern Co. Roscommon.
2. Ui Mhaille, who were the O’Malleys mentioned above, inhabiting the area surrounding Clew Bay in Co. Mayo, known as the Two Umhalls, Upper and Lower.
3. Luigne, the leading sept of which were the O’Haras, and it included the Gailenga, whose leading sept were the O’Garas. The territory included the barony of Leiney in Co. Sligo and the barony of Gallen in Co. Mayo.
4. Gregraighe, the leading sept of which may have called O’Greggs, who held what is now the barony of Coolavin until the Gailenga were expelled from their own territory by the MacSurtains (the Anglo-Norman Jordans) and took it for their own.
5. Ciarraige, originally a single kingdom broken up into five parts.
Ciarraige Locha na nAirne, whose leading sept were the O’Cierans, in modern Co. Mayo, in the modern barony of Costello, who were, in fact, the leading sept of the all Ciarraige.
Ciarraige Aei, also known as Clann Ceithearnaigh, of the Maigh Aei, home of the Sil Murray to whom they were subject early on, in what is now central Co. Roscommon
Ciarraige Airtech in the Magh nAirtech in modern northwest Co. Roscommon, the civil parish of Tibohine, also in Sil Murray
Ciarraige Oic Beathra, who lived among the Ui Fiachrach Aidne and were subject to them.
Ciarraige Uachtar, in the modern barony of Clanmorris, divided into the territories of Tir Nechtan and Tir Enda.
6. Conmaicne, of which there were five groups in Connacht
Conmaicne Mara, in the modern barony of Ballynahinch, Co. Galway, whose leading sept were the O’Kealys. Other septs were the MacConneelys, the O’Clohertys, the O’Devaneys, and the MacFalons, who were their brehons. After the O’Flahertys took Tir Da Locha and Connemara for their own, the O’Kealys emigrated to Ui Orbsen, now the barony of Ross. In the 12th century, these were the only Conmaicne in Connacht not yet a subject tribe.
Conmaicne Cuile Tolad, also known as Conmaicne Meic Oirbsen Mair, whose leading sept were the O’Talorans in the modern barony of Kilmaine, Co. Roscommon.
Conmaicne Magh Rein, whose chiefs were the MacReynolds, centered on the modern barony of Mohill. They were conquered and made subjects early on by the Ui Briuin Breifne. A cadet branch known as the Muintir Annalaigh became the O’Farrell princes of Annally in the later Co. Longford.
Conmaicne Duna Mhoir, also known as Conmaicne Cenel Dubain, whose chiefs were the O’Sheehans. They occupied the area known as Cenel Dubain in the later barony of Dunmore, Co. Galway.
Conmaicne Maenmaigh, also known as Conmaicne Críche Meic Erca, who gave their name to the parish of Kilconickney in Loughrea, Co. Galway, they were subject early on to the Ui Fiachrach Finn.
7. Partraige, of which there were three groups
Partraige Ceara, whose kings were the O’Garvalys. The territory took in roughly the modern barony of Carra in Co. Mayo. After the influx of the Ui Fiachrach branch known as Fir Ceara, whose kings were the O’Murrays, O’Tierneys, and O’Gormans, these Partraige were confined to Odhbhna, later known as Ballyovey, now called Partry.
Partraige Locha, whose chiefs were the O’Dorchys, took in roughly the modern parish of Cong in the baronies of Ross, Co. Galway, and of Kilmaine, Co. Mayo. These Partraige were absorbed into Conmaicne Cuile Tolad during the 7th or 8th century.
Partraige an t-Sleibh, whose kings were the O’Kynes. Their territory correlated to the modern barony of Ross and was also called Ui Orbsen according to some records. In the 13th century, the O’Kealys of Conmaicne Mara arrived after the O’Flahertys swarmed into their territory along with that of their neighbors, the Debhna Tir Da Locha. The Joyces came just a half century later and the territory became Joyce Country, but they were more hospitable overlords than their southern neighbors.
8. Delbhna, of which there were four groups in Connacht (and four in Midhe)
Delbhna Tir Da Locha, the kings of which were the MacConroys. Their territory was called Tir Da Locha, Land of the Two Lakes, contiguous with in the modern barony of Moycullen. The MacConroys ruled directly in Gnomore, while their cadets, the O’Heaneys, ruled Gnobeg. They were pushed out by the refugee O’Flahertys in the 13th century, the MacConroys migrating to Ballmaconry in Connemara and Ballyconry on the coast of Thomond in Munster while the O’Heaneys moved first to the Renvyle Peninsula in Connemara then to Claregalway on east of River Galway. In the 12th century, these were the only Delbhna not yet a subject tribe.
Delbhna Cuile Fabhair, who ruled Maigh Seola until conquered by the Ui Briuin who became the Muinti Murchada then the O’Flahertys, after which they became a subject tribe, though still acknowledged as kings even by their overlords.
Delbhna Nuadat, whose kings were the O’Flannagans until they were conquered by and became a subject tribe of the Ui Maine.
Delbhna Sith Neannta, whose chiefs were the O’Logues. Their territory occupied the small area now called the townland of Fairymount in the barony of Ballintober in Co. Roscommon, and they were subject early on to the Sil Murray.
9. Corca, also called Cuirca and Corcraige in the Book of Rights as well as Corco or Corcu elsewhere
Corca Fir Tri were the main tribe of note named “Corca” in what is traditionally thought of as the kingdom of Connacht. Their leading sept were the O’Devlins. Once independent and separate, they became part of the kingdom of the Luigne and Gailenga and provided at least a few of its kings.
Corca Achlann, whose chiefs were the MacBrennans and the O’Mitchells in the modern barony of Roscommon, were another group.
Corca Mogha, whose chiefs were the O’Scahills and the O’Broins, in the parish of Kilkeeran in the barony of Killian in Co. Galway were yet another group.
There were also two tribes in what is now County Clare and was once part of Connacht until the ninth or tenth century that were termed Corco or Corca whose presence undoubtedly dated back to the time when the area belonged to the province.
Corca Mruad in the northwest corner of what is now Co. Clare in what became Tuadh Mumhan (Thomond) under the Dal gCais (whose leading septs were the O’Briens) in the 10th century. The chiefs of the tuatha were the O’Connors, unrelated to the dynasty that ruled Connacht. Around the 12th century, the tuatha split into northern and southern branches, the latter retaining the name Corca Mruad (now the barony of Corcomroe) and the ruling dynasty while the latter became Boiren, ruled by the O’Loughlans. Another sept of Corca Mruad was named the O’Flahertys, unrelated to the O’Flahertys of Muintir Murchada.
Corca Baiscinn in the southwest of modern Co. Clare, whose chiefs became the O’Baskins, related to the Dal Riata of Ulster and Argyll as well as the Muscraige and Corca Duibhne of Mumhan. They too divided into two halves, east and west, one under the O’Baskins and the other under the MacDermots. After the rise of the Dal gCais, both fell under the MacMahons of that tribe.
Tribal kings receiving stipends from Cruachan
In ancient Ireland, paying honor and respect went down as well as up, and the high king of all Connacht paid annual stipends to a number of kings in the province. These included the kings of the following tribes:
1. King of Sil Murray
2. King of Umhall
3. King of Gregraighe
4. King of Delbhna (probably Tir Da Locha)
5. King of Conmaicne (probably Mara)
6. King of Ui Maine
7. King of Luigne
8. King of Ui Briuine (probably Breifne)
9. King of Ui Fiachrach Muaidhe
10. King of Cenel nAeda
11. King of Partraige (probably Carra)
Subject tribes of Connacht
The subject, tribute paying tribes of Connacht called Aithechtuatha, residents of tricha cets ruled by members of the dominant regional dynasty are too numerous to list individually, and, frankly, too complex to sort out, and would be far too lengthy for a mere blog entry. None are listed in the Book of Rights, but some are known from other sources. Here’s some of the more interesting.
The Ui Cairpri in northern Co. Sligo and northeast Co. Leitrim, whose leading sept became the O'Mulclohys of Carbery
The Sogain, later written Sodhan, were a tribe of Cruithne who became subject to and followed Ui Briuin Seola and whose leading sept became the O’Mannings.
The Calraige were another group not listed in the Book of Rights and they had around a dozen or so branches in Connacht, mostly in barony of Tirerag.
The Mescraige were in Breifne (Tuisceart Connacht); their chiefs became the MacGoverns of Tullyhaw while their cadets became the MacTiernans of Tullyhunco, both in Co. Cavan.
The Clan Tomaltaigh retained the name into the historical era; their chiefs were the MacGeraghtys of Muintir Rodhuibh in the barony of Roscommon.
The Three Tuatha in Teora Connacht included the Corca Achlan, the Cenel Dobhtha, and the Muintir O’Monaghan, the last of which tried to pass as Ui Briuin na Sinna
The Seincheinol were the tribes of the original Fir Bolg territory conquered by the Ui Maine, which did not include the later conquests of Delbhna Nuadat and Ui Fiachrach Finn
Leading tribes of Connacht up to the mid-11th century
After the overthrow of the Fir Ol nEchmachta, the Ui Fiachrach gave the province its first kings from the Connachta. They began alternating with the Ui Briuin in the late 5th century until the early 8th century, after which, with one exception, the Sil Murray and Sil Cathail septs alternated until the former eclipsed the latter entirely at the end of the century. The original chiefs of Sil Murray became the O’Connors in the late 800’s and as high kings of all Connacht separate from their parent tribe.
Modern Ireland is divided into counties. Counties are divided into baronies. Baronies are divided into (civil) parishes. Parishes are divided into townlands. In the list below, a place name without a designator before the name of a county is a parish; a place name without a designator before a barony is a parish; a place name before a parish without a designator is a townland, or bally, from Irish “baile”.
Several baronies in Connacht, and in the rest of Ireland, have identical names to some counties, and often there are more than once of these, but usually in the county of the same name. The barony of Roscommon is in Co. Roscommon. There is a barony of Leitrim in Co. Leitrim. There is a barony of Longford in Co. Longford. Co. Louth has a barony of Louth. There is a barony of Monaghan in Co. Monaghan. Co. Galway, is the worst offender, you might say, with another barony of Leitrim, another barony of Longford, a barony of Clare, and a barony of Galway, as well as a barony of Ballymoe, which is also the name of a barony in Co. Roscommon.
This list is more or less from north to south, from Cos. Leitrim and Cavan, to Cos. Mayo and Sligo, to Cos. Roscommon and Galway, with the three known tribes of pre-Dal gCais Co. Clare which were likely part of the original Connacht.
Chiefs “of” a territory were of its dominant sept; chiefs “in” a territory were of subject sept. In contemporary records of the time, all or most of these were called kings; the use of the titles lord and chief comes from post-Conquest annalists.
Long before the 11th century, the Ui Ailello of Iochtar Connacht had been crushed between the Ui Fiachrach Muaidhe to their west and the Ui Briuin Breifne to the east.
Airthir Connacht and part of Iochtar Connacht
O’Rourke, kings of Breifne, once Cos. Leitrim and Cavan, now just Co. Leitrim
O’Reilly, princes of Muintir Maoilmhordha, now Co. Cavan
MacTiernan, chiefs of Tullyhunco, Co. Cavan
MacGauran (Magovern), chiefs of Tullaghagh, Co. Cavan
Mac-a-Naw (Ford), chiefs of Clan Kenny, Innismagrath, Drumaghaire, Co. Leitrim
MacCogan, chiefs of Clan Fearmaighe, Drumaghaire, Co. Leitrim
MacDarcy, chiefs of Cenel Luachain, Mohill, Co. Leitrim
MacClancy, chiefs of Dartraige, now Ross-Clogher, Co. Leitrim
O’Finn, chiefs of Calraige (Calry) in Cos. Leitrim and Sligo
O’Carroll, chiefs of Calraige (Calry) in Cos. Leitrim and Sligo
MacMallison, chiefs of Magh Breacraighe on the borders of Cos. Leitrim and Longford
MacFinvar, chiefs of Muintir O’Gearan, in Co. Leitrim
MacReynolds, chiefs of Muintir Eoluis, now the baronies of Leitrim, Mohill, and Carrygallen in Co. Leitrim
O’Mulvey, chiefs of Magh Nisi, west Co. Leitrim
MacBrady, chiefs in Muintir Maoilmhordha
MacGilduff, chiefs of Tullgarvey, Co. Cavan
Tuisceart Connacht and part of Iochtar Connacht
O’Dowd, kings of Tuisceart Connacht and Tir Amhalagiadh, modern Cos. Mayo and Sligo
O’Cowan, chiefs of Ui Fiachrach Muaidhe in the baronies of Tireragh, Corran, and Costello
O’Mulclohy (Stone), chiefs of Cairbre, now the barony of Carbery, Co. Sligo
MacDermott, marshalls of Connacht, chiefs of Tir Oliolla, now the barony of Tirrell, Co. Sligo, later princes of Moylurg, Co. Roscommon and princes of Coolavin, Co. Sligo after deposing the O’Garas, rulers of Tir Tuathail, Arteach, and Clan Cuain.
MacDonough, cadets to the MacDermotts, chiefs of Tirrell after them, chiefs of Corran, now the barony of Corran, Co. Sligo
O’Hara, kings of Luigne, now the barony of Lieney, Co. Sligo, which once also took in the baronies of Costello and Gallen in Co. Mayo
O’Gara, chiefs of Gallen (Gailenga, Sliabh Lugha) until expelled by the MacSurtains, chiefs of Coolavin under the MacDermotts
O’Devlin, chiefs of Corca Fir Tri, Corran, Co. Sligo
O’Murray, kings of Fir Ceara, now the barony of Carra, Co. Mayo, and of Lagan district in the Tirawley, Co. Mayo
O’Gorman, chiefs in Fir Ceara
O’Tierney, chiefs in Fir Ceara
O’Catney, chiefs of Cenel Fedhliniadh (Iorras Domnann), now the barony of Erris, Co. Mayo
O’Callaghan, chiefs in Iorras Domnann
O’Minahan, chiefs in Iorras Domnann
MacCoinin, chiefs in Iorras Domnann
O’Gaughan, chiefs in Calraige Moy Heleog, now the parish of Crossmolina, Co. Mayo
O’Molina, chiefs in Calraige Moy Heleog, Crossmolina, Co. Mayo
O’Loughnan, chiefs of the Two Bacs, now the parish of Backs, Co. Mayo
O’Milford, chiefs in Ui Eachach Muaidhe between Ballina and Killala
O’Mulrennin, chiefs in Ui Eachach Muaidhe
O’Managan, chiefs of Breach Magh in the parish of Kilmore Moy, Co. Sligo
O’Connellan, chief s of Bonnyconnellan, Gallen, Co. Mayo
O’Cieran, chiefs of Bellahawnes (Ciarraghe Loch-na-nAirdneadh), Costello, Co. Mayo; at one time the territory took in parishes of Aghamore, Bekan, Ballyhaunis, and Knock.
O’Conaty, chiefs of Cabra in Tireragh, Co. Mayo
O’Quinn, chiefs of Clann Cuain with O’Mulleeney and MacFlannagan, Castlebar, Co. Mayo
O’Cavan, chiefs of Tuath Ruisen, Carra, Co. Mayo
O’Connor, high kings of all Connacht
MacGeraghty, kings of Sil Murray
O’Mulconry, chief bards and historians of Connacht, Clooncraff, barony of Roscommon
O’Flannagan, chiefs of Sil Cathail, barony of Roscommon
O’Moore, chiefs in Sil Cathail
O’Carthy, chiefs in Sil Cathail
O’Moran, chiefs in Sil Cathail
O’Finaghty, chiefs of Clan Conway and Clan Murchada
O’Fallon, chiefs of Clan Uadach, Athlone, Co. Roscommon
O’Hanley, chiefs of Cenel Dobhtha (one of the Three Tuatha), Balintober, Co. Roscommon
O’Hanly, chiefs of Cenel Dobtha (one of the Three Tuatha), Co. Roscommon
MacBrennan, chiefs of Corca Achlan (one of the Three Tuatha), Co. Roscommon
O’Mitchell, chiefs of Corca Achlan (one of the Three Tuatha), Co. Roscommon
O’Monaghan, chiefs of Muintir O’Monaghan (one of the Three Tuatha), aka Tir Briuin na Sinna
O’Beirne, chiefs of Muintir O’Monaghan (one of the Three Tuatha), Balintober, Co. Roscommon
O’Mulrenan, chiefs of Clan Connor, barony of Roscommon
O’Cathalin, chief of Clan Fogarty, Balintober, Co. Roscommon
O’Mooney, chiefs of Clan Clan Murthuile, Balintober, Co. Roscommon
O’Concannon, chiefs of Ui Diarmida, in Athlone, Co. Roscommon and Ballymoe, Co. Galway
MacGeraghty, chiefs of Muintir Rodhuibh (Clan Tomaltaigh) in Co. Roscommon
MacMurrough, chiefs in Muintir Rodhuibh (Clan Tomaltaigh) in Co. Roscommon
O’Flynn, chiefs of Sil Maolruin, Balintober, Co. Roscommon
O’Mulmay, chiefs of Clan Teige Sil Maolruin, Balintober, Co. Roscommon
O’Roland, chiefs of Coill Fothaidh on the borders of Cos. Mayo and Roscommon
O’Skahill, chiefs of Corca Mogha (Corcamoe) of Kilkeeran, Killian, Co. Galway
O’Farrell, princes of Annaly (Muintir Anghaile), equal to Co. Longford
O’Ronan, chiefs of Cairpre Gabra
O’Quinn, chiefs of Muintir Magilligan
O’Mulfinney, chiefs of Corcard
MacCaron, chiefs of Muintir Maelsinna
O’Sheehan, chiefs of Cenel Dubain, Dunmore, Co. Galway
O’Molloy, chiefs of Clann Taidg, Co. Galway
O’Flaherty, kings of Muintir Murchada, now the barony of Clare, Co. Galway, and titular kings of Iar Connacht beginning in the 11th century
O’Faherty, kings of Delbhna Cuile Fabhair and chiefs of Muintir Faghartaigh and Fiodh Luaraigh
O’Lee, princes of Ui Briuin Seola and erenaghs of Annaghdown, Co. Galway
O’Daly, chiefs of Ui Briuin Ratha, Clare, Co. Galway
O’Duan, erenaghs of Killursa, Annaghdown, Clare, Co. Galway
O’Halloran, chiefs of Clan Fearghaill, Dunkellin, Co. Galway
MacCarney, chief s of Meadhraighe (Maree), now Ballynacourty, Dunkellin, Co. Galway
MacGowan, chiefs of Meadhraighe (Maree)
MacHugh, chiefs of Clan Cosgraig, Co. Galway
MacConroy, kings of Delbhna Tir Da Locha, now the barony of Moycullen
MacAneave (Mac Giolla na Naomh, Ford), erenaghs of St. Cuimin, or perhaps of Cloghmore
O’Heaney, erenaghs of St. Enda at Ballynaspiddal, Co. Galway
O’Kealy, kings of Conmaicne Mara, now the barony of Ballynahinch, Co. Galway
MacConneely, chiefs of Ballyconneely, Ballynahinch, Co. Galway
O’Garvaly, kings of Partry (formerly Ballyovey, formerly Odhbhna), Carra, Co. Mayo
O’Kynes, chiefs of Ui Orbsen and Partraige an-t Sliebh, now the barony of Ross, Co. Galway
O’Dorchy, chiefs of Partraige Locha, now the parish of Cong
O’Malley, kings of Tir Umhall, now the baronies of Murrisk and Burrishoole, Co. Mayo
O’Fergus, chiefs in Tir Umhall
O’Tierney, chiefs in Tir Umhall
O’Toole, chiefs in Tir Umhall
O’Taloran, kings of Conmaicne Cuile Tolad, now the barony of Kilmaine, Co. Mayo
Deisceart Connacht, aka Aidne
O’Clery, kings of Deisceart Connacht and leading sept of Ui Fiachrach Aidne, centered on the barony of Kiltartan and in part of Dunkellin, Co. Galway
O’Heyne, princes in Ui Fiachrach Aidne
MacGilkelly, chiefs in Ui Fiachrach Aidne
O’Clery, chiefs in Ui Fiachrach Aidne
O’Diffely, chiefs of Cean Gamhna, Ui Fiachrach Aidne
O’Cahan, chiefs of Cenel Sedna, Ui Fiachrach Aidne
O’Maghna, chiefs of Ceanridhe, Ui Fiachrach Aidne
O’Shaughnessy, chiefs of Cenel Aeda nEchtage, Kiltartan, Co. Galway
O’Cahill, chiefs of Cenel Aeda nEchtage, Kiltartan, Co. Galway
MacFiachra, chiefs of Oga Beathra (Ciarriage Aidne)
Uachtar Connacht, aka Ui Maine
O’Kelly, kings of Uachtar Connacht and leading sept of the Ui Maine
O’Coffey, chiefs of Ui Cobthaigh, Ui Maine
O’Madden, chiefs of Sil Anamchadha, Ui Maine
O’Hoolihan, chiefs in Sil Anamchadha, Ui Maine
O’Mullally (O’Lally), chiefs of Maenmoy (Ui Fiachrach Finn), Ui Maine
O’Naughton, chiefs of Maenmoy (Ui Fiachrach Finn), Ui Maine
O’Donoghoe, chiefs of Clan Cormac, Maenmoy, Co. Galway
O’Connell, chiefs of the area from the River Grian to the plain of Maenmoy, Ui Maine
MacEgan, chiefs of Clan Diarmada, Leitrim, Ui Maine, Co. Galway
O’Fahey, chiefs of Pobal Muintir Ui Faithaigh, Ui Maine, Co. Galway
O’Finnegan, chiefs of Clan Fleming/Muintir Cionaith, Moycaron, Co. Roscommon, subject to the Ui Maine
O’Duibhghind, chiefs of Ui Duibhghind, Leitrim, Co. Galway
O’Donnelan, chiefs of Clan Breasil, Leitrim, Co. Galway
O’Docomlain, chiefs of Eidhnigh, Loughrea, Co. Galway
O’Gauran, chiefs of Dal Druithne, Loughrea, Co. Galway
O’Scahill, chiefs of Corca Mogha, Kilkeerin, Killian, Co. Galway
O’Brion, chiefs of Lough Gealgosa, Kilkerrin, Killian, Co. Galway
O’Mulbride, chiefs of Magh Finn and Bredagh, Athlone, Co. Roscommon
O’Mannin (O’Manning), chiefs of Sodhan, Tiaquin, Co. Galway. Their sub-chiefs were O’Lennon, MacWard, O’Scurry, O’Cashin, O’Gialla, and O’Maigin.
O’Cahill, chiefs of Cruffan, Killian and part of Ballymoe, Co. Galway
O’Moran, chiefs of Cruffan
O’Mulroney, chiefs of Cruffan
O’Leahy, chiefs of Caladh, Kilconnell, Co. Galway
MacGilduff, chiefs of Caladh
MacNevin, chiefs of Crannagh MacNevin, Tynagh, Leitrim, Co. Galway
MacKeogh, chiefs of Onagh, Taghmaconnell, Athlone, Co. Roscommon
These are some of the leading families in the area when it formed the southernmost portion of the kingdom of the Ui Fiachrach Aidne in Connacht, before the a group of Eoghanachta arrived from Munster and conquered the area for their own in the 8th century. Two centuries later, they in turn were displaced by rise of the Dal gCais, the Deisi Tuaisceart of the east of the area under a new name.
By the 11th century, of course, the Dal gCais were overlords of nearly all the region as well as of Munster, but these roughly reflect the spheres of influence at the time they lay under the domination of the Ui Fiachrach, before the area was “Tuadh Mumhan”. The tribes other than the Dal gCais are probably descended from the Gangani of Ptolemy’s map and in his time.
O’Connor, kings of Corcomroe
O’Loughlan, kings of Burren
O’Donnells, kings of Baiscind
O’Baskin, chiefs of Baiscind
O’Hehir, chiefs of Hy Cormaic (barony of Islands minus parish of Clondagad)
O’Dea, chiefs of Kineal Fearmaic (barony of Inchiquin)
O’Curry, kings of Deisi Tuaisceart and chiefs of Ui Oenghusa
O’Brien, chiefs of Ui Toirdhealbhaigh
MacNamara, chiefs of Ogashin
O’Kennedy, chiefs of Omulled
O’Shanahan, chiefs of Ui Ronghaile
O’Durack, chiefs of Ogonnello
O’Ahern, chiefs of Ui Cearnaigh
MacKeogh, chiefs of Owney (Uaithni), now Owney (Uaithni Thire) in Co. Limerick, over which they were directly chiefs, and Owneybeg (Uaithni Cliach) in Co. Tipperary, over which the O'Cahalanes were chiefs under them. The other septs are the O’Heffernans and the O’Lynchs. They occupied most of northern Aidne and perhaps some of Iar Connacht at the turn of the era until the Ui Fiachrach arrived, when they moved to what is now eastern Co. Clare, from which they were later displaced by the Deisi Tuaisceart.
The Corco Mruad Arann were kings of the Islands of Aran until the 8th century, when they were displaced by the Eoghanachta Ninussa. In the mid-12th century, these were in turn displaced by MacTeige O’Briens.
Crichaireacht cinedach nduchasa Muintiri Murchada, a tract listing the territories and chiefs of Muintir Murchada before the expulsion of the O’Flahertys, c. 11th century
The Four Masters. The Annals of the Kingdom of Ireland, compiled 1632-1636
John O’Donovan, translator. The Book of Rights, written 5th century CE, published 1848
John O’Donovan and Eugene Curry. Ordnance Survey Letters, 1839. Clare County Library.
John O’Donovan, translator. The Topographical Poems of John O’Dugan, published 1862
Roderic O’Flaherty. A Chorographic Description of West or h-Iar Connaught, 1684
James Hardiman. “A Chorographical Description of West or H-Iar Connaught Written A. D. 1684, Edited, from a Ms. In the Library of Trinity College, Dublin, with Notes and Illustrations”. Journal of the Irish Archaeological Society, 1848
John O’Hart. Irish Pedigrees, or the Origin and Stem of the Irish Nation, 1892
“Ireland’s History in Maps” website.
Various Irish related articles on Wikipedia
Those are the main sources; various other websites, webpages, books, magazines, tracts, etc. were used to verify some of the info.