Longfield. English origins.  They have been in Co. Cork in Southern Munster since the Mid - 17th Century AD.

O Lonnain. They were in the west of Co. Cork in Southern Munster. See O Lennon or O Lenane.

O Looby. See - Luby.

O Loon. A Heremonian Ui Cobhthaigh Dal Cuinn Colla da Crioch Cenel Rochada Fernmag (Fer Fermaighe) Farney Sept / Family branch, who had their territory at Farney in Co. Monaghan in Southern Ulster in the kingdom of Orghialla / Airghialla / Oriel. Especially see - O Loan.

O Loonan or O Loonane - Irish / Ua Luanain - luan / hound or warrior. A Sept / Family branch, who had their territory in Co. Longford in the north - west of Northern Leinster.

Mac Loone. Used as a variant for Mac Glone, which see - Irish /  Mheic Colluin. A Sept / Family branch, who had their territory in the Glenties in Co. Donegal in the north - west of the Ulster Province. Mac Aloon also used there.

O Looney - Irish / Ua Luanaigh. A Sept / Family branch, who had their territory in Co. Clare in the north - west of Thomond / Tuaisceart Mhumhan / Northern Munster  and were also in Co. Cork in Southern Munster. Not connected to Lunney or Lowney.

O Looran or O Loran. Used as variants for O Loughran, which see, in Co. Meath and Co. Westmeath in the south of Northern Leinster.

O Lorcan. A Heremonian Ui Cobhthaigh Dal Cuinn Colla da Crioch Airthir Ui Niallain Clann Cernaich Sept / Family branch, who had their territory at Oneilland East and West in Co. Armagh in the south - east of the Ulster Province and the adjacent country in Co. Monaghan in Southern Ulster where they were  the Chiefs of Farney and West Ui Breasail. Especially see - O Larkin.

O Lorcayne. A Heremonian Ui Cobhthaigh Dal Cuinn Colla da Crioch Airthir Ui Niallain Clann Cernaich Sept / Family branch, who had their territory at Oneilland East and West in Co. Armagh in the south - east of the Ulster Province and the adjacent country in Co. Monaghan in Southern Ulster where they were  the Chiefs of Farney and West Ui Breasail. Especially see - O Larkin.

Lord. Used as a synonym for Kiernan and Tierney, which see - Irish - tighearna / lord. 

Lord. English origins. They were in Co. Dublin in the north - east of Southern Leinster and nearby in Co. Westmeath in the south - west of Northern Leinster in the Mid - 17th Century AD.

O Lordan - Irish / Ua Lordain. A Sept / Family branch, who had their territory in the west of Co. Cork in Southern Munster.

Lorimer -

Mac Lorinan. See - Mac Larnon.

O Lorkan or O Lorkin. Used as variants for O Larkin, which see. A Heberian Dal gCais Sept / Family branch, who had their original territory in Co. Clare in the north - west of Thomond / Tuaisceart Mhumhain / Northern Munster. Ancestors - *104.Cosgrave / Coscrach, *103.Lorcan / Fingin, *102.Lachtna, *101.Corc, *100.Anluan, *99.Mahon, *98.Turlough (Ui Turlough), *97.Cathal, *96.Aodh "Caomh" the King of Munster, *95.Conall, *94.Eochy / Eochaidh "Baill Dearg," *93.Cairthenn "Fionn  Oge Mor," *92.Blood / Blod (Ui Bloid), *91.Cas (Dal gCais) the King of Thomond.

O Lorking. A Heremonian Ui Cobhthaigh Dal Cuinn Colla da Crioch Airthir Ui Niallain Clann Cernaich Sept / Family branch, who had their territory at Oneilland East and West in Co. Armagh in the south - east of the Ulster Province and the adjacent country in Co. Monaghan in Southern Ulster where they were  the Chiefs of Farney and West Ui Breasail. Especially see - O Larkin.

O Lorrigan. Used as a variant for O Lonergan, which see.

Mac Loskey. Used as a variant for Mac Cluskey, which see.

Losse -

O Losty - Irish / Ua Loiste. A Sept / Family branch. who had their territory in Co. Donegal in the north - west of the Ulster Province.  O Lasty, O Lastly and O Lusty were used as variants. Leslie also used as a synonym.

Lother or Lowther -

Lough. Scottish toponymic origins. Used as a variant for Loch, which see. They have been in the Ulster Province since the early 17th Century AD after the Confiscation of the 3,500,000 acres of the Heremonian Ui Cobhthaigh Dal Cuinn "Northern" Ui Niaill territories by the English and the Foreign non - Catholic Plantations there.

O Loughan. See - O Lohan.

Lougheed. Scottish origins. Used as a variant for Lochead / head of the loch - akin to Kinloch / ceann an locha - in Gaelic, which see.

O Loughlin or O Lochlainn - Irish / Ua Lochlainn - loch / lake - lann / land. An Irian Sept / Family branch of the Clan na Rory Tuath / Family region (Descended directly from *Lochlann) a Chief of their territory in Corcomroe in Co. Clare in the north - west of the Munster Province. *Lochlainn was descended from the Irian Kings of Ulster who were in turn descended from *37.Ir the Milesian Gaelic Celtic brother who was drowned during the expedition to Ireland in 1699 BC. They were Chiefs of the Burren in the east of Corcomroe  and kinsmen to the O Connors the Chiefs of Fear Arda and Corcomroe, the O Donnells, the O Baskins, the O Keelys and the O Kellys the Chiefs of Corca Baiscinn and the O Mulcoras there. *62.Rory “Mor” / the Greater was the Irian 86^th King of Tara / Erinn who died in 218 BC who is the ancestor of the Irian Families from the Clann na Rory. The son of his fifth son was *64.Fergus ”Mor” and his sixth son was the ancestor of *68.Conal “Cearnach” - of the Victories the leader of the Knights of the Red Branch of Ulster. *68.Conal "Cearnach" was also the forefather of the O Moores, Mac Guinness, Mac Gowans, and many other important Irian Families in the Ulster Province, the Leinster Province and the Connacht Province. Ancestors - *Lochlann - *62 Rory "Mor" the 86th King of Tara / Ireland (Clann na Rory), *37.Ir (Irians).

O Loughlin - Irish / Ua Lochlainn - loch / lake - lann / land. A Heberian Dal gCais Sept / Family branch, who had their original territory in Co. Clare in the north - west of Thomond / Tuaisceart Mhumhain / Northern Munster. See also Loughnane. Ancestor -*91.Cas (Dal gCais) the King of Thomond.

Mac Loughlin or *O Melaghlin - Irish / Ui Maiolsheachlainn (Descended from a devotee of St. Sechlainn) A Heremonian Ui Cobhthaigh Dal Cuinn "Southern" Ui Niaill Clann Cholmain Sept / Family branch, who had their territory in Co. Westmeath in the south - west of Northern Leinster. (Directly descended from *104.Malachy 11 / Maol Sechlainn the 40th King of Meath and 169th High King of Ireland) who died in 1022 AD. Later corrupted to O Melaghlin, which see, and then Mac Loughlin. Ancestors - *104.Malachy 11, *103.Donnell / Domhnall, *102.Donough / Donnchad "Donn" the 166th King of Ireland, *101.Flann "Sinna" the 164th King of Ireland, 100.Malachy 1st  / Mael Sechlainn the 162nd High King of Ireland, *99.Mael "Ruanaid," *98.Donough / Donnchad "Midi" the 158th King of Ireland, *88.Conall "Cremthainne," *87.Niall of the Nine Hostages the 126th King of Tara / Ireland.

Mac Loughlin or *Mac Laughlin or O Loughlin - Irish / Ui and Mheic Lochlainn - loch / lake - lann / land. A Heremonian Ui Cobhthaigh Dal Cuinn "Northern" Ui Niaill Cenel nEogain Sept / Family branch descended from *105.Ardgar the 44th King of Aileach, a son of *104.Lochlainn, who had their territory at Inishowen in Co. Donegal and in Co. Derry in the north - east of the Ulster Province. They were the most powerful family in Ulster during the Middle Ages, but lost their importance during the 13^th Century AD. Their name is usually anglicized there as *Mac Laughlin. Ancestors - *108.Murtough Mac Loughlin / Muirchertach Mheic Lochlainn, *107.Niall Mac Loughlin, *106.Donnell / Domhnall Ua Loughlin, *105.Ardgar, *104.Lochlann, *88.Eogan the 1st King of Aileach, *87.Niall of the Nine Hostages the 126th King of Tara / Ireland.

Mac Loughlin - Irish / Mheic Lochlainn - loch / lake - lann - land. A Heremonian Ui Cobhthaigh Dal Cuinn Ui Briuin Sept / Family branch, who had their territory in the Connacht Province where the were kinsmen to the Ui Briuin Ai Septs of the O Connors and Mac Dermots. Ancestors - *103.Conor / Conchobar the 38th King of Connacht, *102.Teague / Tadhg "Mor," *101. Muirgius the 31st King of Connacht, *100.Tommaltach, *99.Murgal, *98.Indrechtach the 21st King of Connacht, *97.Murray / Muiredach "Muillethan" (Ui Muiredaig) the 18th King of Connacht,*96.Fergus / Muirgius, *95.Reilly / Ragallach the 12th King of Connacht (Ui Briuin Ai), *87.Brion the original 1st King of Connacht (Ui Briuin), *86.Eochy "Mugmedon" the 124th King of Tara / Ireland.

Mac Loughlin or Mac Lachlan - Irish / Mheic Lochlainn, A Heremonian Ui Cobhthaigh Dal Cuinn Colla da Crioch Siol Daim Argait (Ui Cremthainn) Clann Lugainn Sept / Family branch of the Maguires who had their territory in Co. Fermanagh in the south - west of the Ulster Province. Kinsmen also to Mac Alear / Mac Eleer / Mheic Gilla Uidhir, Mac Aleese / Mac Gileece / Mac Leece / Mac Illeese / Mac Leese / Mac Lice / Mac Lise etc / Mheic Giolla Iosa, Mac Anally / Mac Cowley / Mac Culloo / Mheic Con Uladh, Mac Auley / Mac Awley / Mac Gawley / Mheic Amhlaoibh. Mac Breen / Mheic Braoin, Mac Caffrey / Mac Godfrey / Mheic Gafraidh, Mac Cassidy / Mheic Asidha, Mac Cormack / Mheic Cormaic, Mac Court / Mac Courtney / Mheic Cuarta / Mheic Cuairt. Mac Corry / Mac Curry / Mac Corrie / Mac Gorry / Mac Godfrey / Mac Gohery / Mac Goffrey / Mheic Gothraidh, O Darragh / O Darra / O Darrough / Oaks / Ui Dubhdhara, Mac Gee / Magee / Mheic Aodh, O Heany / O Heaney or O Heeny / O Heeney / O Hegney / O Henaghan / O Higny / Mac Anenay / Mac Eneany / Bird / Ui hEgneach / Ua hEighnigh / Ua hEicnig. Mac Lilly / Mac Lillie (originally Mac Alilly) Mac Calilly / Mac Lely / Mac Alyly / Mheic Ailghile, Mac Manus / Mheic Maghnuis, Mac Morrow / Mac Murrow / Mheic Murchada (Clann Aodh). Ancestors - *108.Donn "Carrach" Maguire the King of Fermanagh, *107.Randal Mag Uidhir / Maguire, *106.Odhar "Oge" Mag Uidhir / Maguire, *105.Searrach Mag Uidhir / Maguire, *104.Orgiall / Oriel mheic Uidhir / Maguire, *103.Uidhir, *102.Serrach, *101.Orgiall / Oriel, *100.Odhar / Uidhir, *99.Cearnach, *98.Lugan, *97.Irgalach, *96.Eignigh, *95.Cormac, *94.Fergus, *93.Aed, *92.Cormac, *91.Cairpre "Daim Argait," *90.Eochy / Echach, *89.Criffan / Crimthann "Leith" / "Lethan," *88.Feicc, *87.Dega "Duirn," *86.Rochatha / Rochadh, *85.Murray / Muiredach "Colla da Crioch" / "Focrith" - of the Two Countries, *84.Eochy / Echu "Doimhlen," *83.Cairbre "Liffeachair" the 116th King of Tara / Ireland.

Mac Loughlin - Irish / Mheic Lochlainn. A Sept / Family branch, who had their territory at Loughlinstown in Co. Dublin in the north - east of Southern Leinster.