O Birn. A Sept / Family branch, who had their territory in Co. Mayo in the mid - west of the Connacht Province. See also - O Beirne.

O Birrane - Irish / Ua Biorain - bear / spear. Changed to Byrne, Byron and Burns, which see, in the Connacht Province and the Munster  Province. Cognate with Berrane.

Birt. Used as a variant for Britt, which see. They were in Co. Dublin in the north - east of Southern Leinster in Mediaeval Times.

Birt or Burt or Byrth or Bert. English origins. They have been in Co. Derry in the north - east of the Ulster Province since the 18th Century AD.

Bishop - Irish / Mheic Giolla Easpaig (Descended from a son of the devotee of the Bishop) Used by the Heremonian Ui Cobhthaigh Dal Cuinn "Northern" Ui Niaill Cenel nEogain. See especially, Mac Anespie / Mac Anaspie, Mac Espig and Mac Gillespies, who had their territory in Co. Tyrone in Central Southern Ulster. Ancestor  - 104.Flaherty / Flaithbertach Ua Niaill the 40th / 42nd King of Aileach, 103.Murtough / Muirchertach - 102.Donnell / Domhnall Ua Niaill the 34 / 37th King of Aileach and 168th King of Ireland, *101. Murtough / Muirchertach of the Leather Cloaks the 33rd King of Aileach, *100. Niall "Glun Dubh" (O Neills of Ulster) the 29/30th King of Aileach and 165th King of Ireland,  *99.Aed "Findliath" - *98.Niall "Caille" the 23rd King of Aileach and 161st King of Ireland, *97.Aed "Oirdnide" the 21st King of Aileach and 160th King of Ireland, *96.Niall "Frossach" the 19th King of Aileach and 157th King of Ireland, *95.Fergal the 17th King of Aileach and 151st King of Ireland - *94.Mael "Duin" the 14th King of Aileach, *93.Mael "Fithrich" the 10th King of Aileach, *92. Aed "Uardidnach" the 8th King of Aileach and 140th King of Ireland, *91.Donnell "Ilchegach" the 4th King of Aileach and 134th King of Ireland, *90.Murtough / Muirchertach mac Ercae the 3rd King of Aileach and 131st King of Ireland, *89.Murray / Muiredach the 2nd King of Aileach, *88.Eogan (Cenel nEogain) the 1st King of Aileach, *87.Niall of the Nine Hostages the 126th King of Tara / Ireland (Ui Niall).

Bissett. Scottish origins. They were in the Glens of Co. Antrim in the north - east of the Ulster Province, and it was also changed to Mac Keown, which see. Gaelic Irish / Mheic Eoin.

Blacagh. Used as a synonym for Blake, which see, in the Connacht Province.

Black. Scottish origins. From the Lamonts, Mac Gregors and Mac Leans of Duart who were in the Ulster Province.

Black / Dubh. Used as a synonym for Duff and Kilduff, which see.

Blackall or Blackhall (dweller by the dark nook.) They were in the Ulster Province, and Co. Limerick in the mid - north - west of Thomond / Northern Munster in the Mid - 17th Century AD, and are now in Co. Limerick and Co. Clare in the north - west of Munster, and Co. Dublin in the north - east of Southern Leinster.

Blackburn or Blackburne. English toponymic origins. They were from Lancashire and have been in Ireland since the 14th Century AD and later, and were "Landed Gentry" in Co. Roscommon in the east of the Connacht Province to Co. Donegal in the north - west of the Ulster Province. (They also had a sub - branch in Co. Meath in the south - east of Northern Leinster.) Variants also used including, Blackbyrne.

Blacker / Bhlaicear. Norse origins. They have been in Co. Armagh in the south - east of the Ulster Province since the Mid - 17th Century AD after the Confiscation of the 3,500,000 acres of the Heremonian Ui Cobhthaigh Dal Cuinn "Northern" Ui Niaill territories there, and the non - Catholic Plantations there.

Blackney. English toponymic origins. They were in Co. Dublin in the north - east of Southern Leinster, and then in Co. Carlow in Southern Leinster since the Mid - 17th Century AD.

Blair. Scottish territorial name. They were in north of the Ulster Province.

Blake / de Blaca / Le Blaca (the black.) One of the "14 Foreign Tribes of Galway," descended from Richard Caddell the English Sheriff of the Connacht Province in 1303 AD, where they were extensive landowners in Co. Galway in the south - west of Connacht. At Renvyle in Co. Galway is the ruined O Flaherty Castle that they took over, which was later attacked unsuccessfully by the Pirate Queen, Grace O Malley. Menlough Castle on the east bank of Loch Corrib in Co. Galway was another of their castles, and they had another at Castlebar in Co. Mayo in the mid - west of Connacht. One of their sub - branches also went to Co. Kildare in Central Southern Leinster where there are 3 town lands known as Blakestown. See also - Blowick.

Blanchard / Bhlainsear. They were in Co. Dublin in the north - east of Southern Leinster.

Blanchfield. Originally de Blancheville. Norman origins. They have been in Co. Kilkenny in the south - west of Southern Leinster since the 13th Century AD.

Blaney. They came from Wales at the end of the 16th Century AD, and were in Co. Monaghan in Southern Ulster where there is Castle Blayney.

O Bleahan or O Bleheen - Irish / Ua Blichin. A Sept / Family branch, who had their territory in the east of Co. Galway in Southern Connacht. Synonymous with Melvin, which see.