The Uí Meic Uais descend from one of the three Collas, i.e. Colla Óiss (Uais), an early pedigree citing Furudran (died c. 642) son of Béc m. Cuanach m. Dairi m. Feidlimidh m. Feichin m. Fiachrach Tuirtich m. Eirc m. Colla Uais m. Echach Doimlen. Francis Byrne in his Irish Kings and High Kings states that the Uí Maic Caírthinn south of Lough Foyle, the Uí Fiachrach Arda Sratha and Uí Thuirtri west and east of the Sperrins, were collectively known as the Uí Macc Uais. However, groups of this name are also noted in the midland region. A genealogy of the Uí Meic Uais:   (Book of Ballymote) Gilla Padraic m. Duibrois m. Donnchada m. Mudroin m. Brain m. Muiredaig m. Aedha m. Flaithbertaich m. Fhirdacrich m. Mailbrigti m. Robartaich m. Coibdeanaich m. Caemain m. Branduib m. Aeda m. Crichain.

The Uí Tuirtre of South Derry moved eastward across the River Bann as their lands were absorbed into the expanding Uí Neill over-kingdom of Cenél Eoghain in the eighth century. They kept their western lands (the present barony of Loughinsholin) as a tributary kingdom to the Cineal Eoghain, but resided in Lough Beg, which lay strategically between their new and old territories. East of the Bann they were allies of the Dal nAraidi, though they profited by their decline. They were also sometimes overkings of Ulidia. The medieval representatives of the Uí Tuirtre were the O’Lynns (O Floinn or O Loinn) of South Antrim, who defeated the Norman John de Courcy when he attempted to invade their territory in 1177. They maintained their independence until about 1368.

Ui Tuirtre - The territory of the Uí Tuitre was also said to have included an area west of Lough Neagh (in modern co. Tyrone), as well as northwest of the great Lough in the modern barony of Loughinsholin, co, Derry. Loughinsholin itself is said to derive from the "lough of the island of the O'Lynns", i.e. the O'Flynn, chiefs of Uí Tuirtre. The O’Beolairts (O Beollain) or Gillanders (Giolla Aindreas) of the Gaelic Cenél Eoghain were co-arbs (hereditary abbots) of St. Maelrubha at Applecross in Ross-shire in Dalriada.

Groups of the Uí Tuitre were apparently driven east across the river Bann by the rise of the O'Cahans about the 12th century, and are later recorded in the central baronies of Co. Antrim, i.e. Toome and Antrim. The Uí Tuirtre genealogy goes back to Fiachu Tuirtri, son of Colla Óiss (Uais). After this time the O'Flynns (O'Lynns) were dominant chiefs of Uí Tuirtre, they being claimed as a senior branch of Clanna Rury of Ulidia. The neighboring territory of Fear Li (Fir Li) was (also?) in the barony of Coleraine (northeast co. Derry), and the O'Flynns (O'Lynns) are cited holding the kingship of both Tuirtre and Fir Li, at various times. O'Dugan (Poems) in the Orghialla section of his poem cite O'Floinn and O'Domhnallain as lords of Uí -Tuirtre. Francis Byrne in his Irish Kings and High Kings states the Uí Maic Caírthinn south of Lough foyle, the Uí Fiachrach Arda Sratha and Uí Thuirtri west and east of the Sperrins were collectively known as the Uí Macc Uais.

An early Ua Tuirtri genealogy:   (Rawlinson) Flann m. Muiredaig m. Muircherdaich m. Flaind m. Muirecáin m. Máel Chráebe (rí Airgialla) m. Duib Sínaich m. Áeda m. Loingsich m. Indrechtaich m. Rechtabrat m. Máel Chráebe m. Máel Fathardaig m. Suibni m. Furudráin m. mBéicce m. Cuanach m. Dáre m. Feidelmid m. Feichíne m. Fiachrach Tuirtle m. Colla Uais.

An early Uí Loind Line .i. Tuitre genealogy:   (Book of Balllymote) Ruaidra m. Domnaill m. Conuladh m. Muircertaigh m. Alaxandair m. Conmuighe m. Conulad in tsighaide m. Conmuighe m. Ruaidri .i. in Deoradh m. Fhoghlogha m. Mc. Iaruind m. Aedha m. Donnugan m. Foghartaich m. Floind (otait Uí Loind) m. Muiredaig m. Indrachtaigh m. Reachtabrat m. Mailcraibhi m. Mailfotartaigh m. Suibni m. Furodran m. Bece m. Cuanach m. Dairi m. Feidhlimthe m. Fechin m. Fiacrach Tuirtri m. Eachach m. Colla Uais.

Feara Li, or Fer Li, i.e. the men of Mag Lí, was located west of the River Bann in the barony of Coleraine, Co. Derry. The Book of Lecan notes that Fir Li (and Uí mac Uais) in Ulster extended from Bir (Moyola river) to Camus (south of Coleraine). The Moyola river was anciently the boundary between the Feara Li and the Húi Tuirtre. The Fir Lí are noted as an Aighiallan people who came under the dominion of the Cenél Eóghain by the 9th century. Their neighbors appear to have been the Uí Tuirtre and factions of both groups are said to have been driven to the east of the Bann (into Ulidia) by the advance of Ua Cathain of the Cenél Éoghain. Another Airghiallan group, the Fir na Chraíbe, were also noted at an early date in the region west of the Bann.

Cruffon, a district containing the barony of Killian and large part of the barony of Ballymoe in co. Galway. O'Hart describes the three chiefs of Crumthan or Cruffan, as O'Cathail (Cahill), O'Mughroin (Moran), and O'Maolruanaidh (Mulrooney or Rooney). Tribes and Customs of Hy Maine cites the Uí Chrumthainn were of Crumthann, aka Cruffon, in Uí Maine. Clann Cremthaind, a sept of Uí Maine, descended from Crimthann Cael, 4th from Maine mór. An O'Mughroin sept is cited as a chief of Clann Cathail in Connacht. A sept of Ua Cathail were lords of Eóganacht Locha Léin in Munster. A sept of O'Maelruanaidh were kings of Moylurg in Connacht. There was also a tribal group of the Clann Colla, in North Ireland, referred to as Uí Cremthainn. Síl Máilruain - From O'Hart comes the following citation. "O'Floinn or O'Flynn, chiefs of Siol Maolruain, a large district in the barony of Ballintubber, county Roscommon; in which lay Slieve Uí Fhloinn or O'Flynn's Mountain, which comprised the parishes of Kilkeeran [i.e. Kilkeevin] and Kiltullagh, and part of the parish of Ballynakill, in the barony of Ballymoe, county Galway. O'Maolmuaidh or O'Mulmay, was a subordinate chief over Clan Taidhg or Clan Teige in the same Uí Maine district of Roscommon-Galway." The Kilkenny Journal of Archaeology places O Flinne's seate was at Ballinlough. The Síl Mailruanaidh, alias Uí Floinn.

(Derlus, Durlais) - The location for a territory named Derlus is described by John O'Donavan in Uí Tuitre, co. Antrim. Note: There was also a Derlas located to the south of Downpatrick, now Bright (Mrechtan), in co. Down, in Uí nEchach country; and yet another cited in Tethba.
As the Ua Floinn (or O'Lynn) are described as chiefs of Durlas in the 12th & 13th centuries, and McLysaght places them in southern Armagh (between Lough Neagh and the sea), perhaps the country of Derlas was on the Armagh-Down border. McLysaght cites the Ua Floinn lineage from Clanna Rury of Ulidia, tracing their descent Colla Uais. Since the reference in the Annals for 'Inis Darcarcrenn' seems to be Ram's Island, near the eastern shore of Loch Neagh, the location of Derlas was likely in county Antrim. The Uí Tuitre of co. Derry are known to have moved west across the river Bann, into county Antrim, supplanting the lands of the Eilne branch of the Dal nAraide by the 10th century. Ua Floinn (O'Flynn, O'Lynn) were Uí Tuirtre leaders as were the later kings of Derlas.