O Forranan. A Sept / Family branch, who had their territory in Co. Donegal in the north - west of the Ulster Province where they were Chiefs.

Forrestall or Forestall. Anglo Norman origins. They were in Co. Kilkenny / Ossory in the south - west of Southern Leinster.

Forsythe - fearsithe (man of peace) Scottish origins. They were in Co. Antrim and Co. Down in the east of the Ulster Province. Also known there as Foursides.

Forth / Fotharta. A Sept / Family branch, who had their territory in Co. Wexford in the south - east of Southern Leinster.

O Fortune or O Fortin or O Forty - Irish / Ua Foirtcheiurn - overlord. A Sept / Family branch, who had their territory in Co. Carlow and Co. Wexford in the south of Southern Leinster. Used as a synonym in Co. Cork in Desmond / Southern Munster for Farshing, which see.

Fottrell. English toponymic origins. They have been in Co. Dublin in the north - east of Southern Leinster since the 15th Century AD.

Fowler. English origins. They have been in the Ulster Province since the Confiscation of the 3,500,000 acres of the Heremonian Ui Cobhthaigh Dal Cuinn "Northern" Ui Niaill territories and the Foreign non - Catholic Plantations there in 1609 AD. See also - Fowloo.

Fowley. Used in Co. Leitrim in Northern Connacht for Foley, which see.

O Fowloo - Irish / Ua Foghladha. See - Foley. Also changed to Fowler, which see.

Mac / O Fox - Irish / Mheic / Ua an tSionnaigh. A Sept / Family branch who were descended from a son of "The Fox," who had their territory originally in Co. Meath in the south - east of Northern Leinster. "The Fox" was the nickname of *Sinnaigh the Chief of Teffia and its use also gave rise to the names Mac Ashinna, Mac Shanaghy, Mac Shinny, Mac Shinnock, Mac Atinney, Mac Tinney and Mac Shannon. *Sinnaigh the actual Fox was in reality *Teige O Kearney / Tadhg Ua Catharnaigh who was the Chief of Teffia in Co. Meath in the 11th Century AD. The Family took over the territory in the Barony of Kilcoursey in Co. Offaly in the north - west of Southern Leinster where his descendants anglicized their name to Fox, but they lost their property there during the Irish Uprising in 1641 - 42 AD. They were also nearby in Co. Westmeath in the south - west of Northern Leinster and Chiefs in Co. Longford also nearby in the north - west of Northern Leinster.

O Foylan - Irish / Ua Faoilean - faol / wolf. A Sept / Family branch, who had their territory at Foylanstown in Co. Westmeath in the south - west of Northern Leinster.

Foyle - fouille / excavation. French origins. They have been in Co. Dublin in the north - east of Southern Leinster since the 13th Century AD and later on they were nearby in Co. Laois in the mid - north - west of Southern Leinster.

O Fraher or O Farraher - Irish / Ua Fearchair - fear char / dear man. A Sept / Family branch, who had their territory in Co. Waterford in the south - east of the Munster Province. Raher used as a synonym there.

O Frahill or O Fraul - Irish / Ua Freathail. A Sept / Family branch, who had their territory in the west of the Munster Province.

O Frahy. See - Frehy.

Frain or Frayne. Used for Freeney in Co. Roscommon in the east of the Connacht Province, and nearby in the north of Co. Mayo in the mid - west of Connacht. Also used for de Freyne.

Frame - frem / stranger. English origins. They were in Co. Kilkenny in the south - west of Southern Leinster in 1577 AD, and later on were in the Ulster Province.

Francis / Le Franceis (the Frenchman) Norman origins -

Francis - Irish / Proinseis. They were near Galway City in Co. Galway in Southern Connacht.

Frank or Franks (the Frenchman). They were in Co. Laois and nearby in Co. Offaly in the north - west of Southern Leinster as "Landed Gentry" in the 17th Century AD and Frankford there was renamed back to Kilcormac.

                                                                                +On to Franke - Frost