Variant spellings are included, so there may be some duplication. If you know of something that should be included, please let me know
| L Estrange |
| L'Estrange |
| La mont |
| Lacey |
| Lacy |
| Ladden Tuam (archived) |
| Ladrigan (archived) |
| Lagan Very extensive (archived) |
| Laghan Very extensive (archived) |
| Laird (archived) |
| Lalee |
| Lalley |
| Lallie |
| Lally |
| Lalor (archived) |
| Lalor (archived) |
| Lalor Laois/Ballarat, Austraila |
| Lalor |
| Lamont |
| Lanagan (archived) |
| Lanagan |
| Lanaghan (archived) |
| Lanaghan |
| Landrigan (archived) |
| Langridge Hercules Langrishe |
| Langrishe Hercules Langrishe |
| Lanigan (archived) |
| Lanigan |
| Lanighan (archived) |
| Lanighan |
| Lanin Wexford |
| Lannagan (archived) |
| Lannagan |
| Lannan Wexford |
| Lannen Wexford |
| Lannigan (archived) |
| Lannigan |
| Lannin Wexford |
| Lannon Wexford |
| Larkan Co. Galway |
| Larken Co. Galway |
| Larkin Co. Galway |
| Latimer |
| Latimore |
| Lattimer |
| Lattimore |
| Laughlin |
| Laughlin |
| Laughlin |
| Laughlin |
| Laughnan Wexford |
| Laughrey |
| Laughry |
| Lavan Roscommon |
| Laven Roscommon |
| Lavin Roscommon |
| Lawler (archived) |
| Lawler (archived) |
| Lawler Laois/Ballarat, Austraila |
| Lawler |
| Lawlor (archived) |
| Lawlor (archived) |
| Lawlor Laois/Ballarat, Austraila |
| Lawlor |
| Le Brun |
| Le Poer Waterford |
| Le Poer (archived) |
| Leacy |
| Leasy |
| Lee Westmeath |
| Leesy |
| Leland |
| Lelland |
| Lenaghan |
| Lenaghan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lenahan |
| Lenahan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lenane Very extensive on Dublin Lennan/Lennon families |
| Leneghan |
| Leneghan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lenehan |
| Lenehan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lenihan |
| Lenihan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lennan Very extensive on Dublin Lennan/Lennon families |
| Lennane Very extensive on Dublin Lennan/Lennon families |
| Lennard Very extensive on Dublin Lennan/Lennon families |
| Lennehan |
| Lennehan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Lennon Very extensive on Dublin Lennan/Lennon families |
| Lenon Very extensive on Dublin Lennan/Lennon families |
| Leonard Very extensive on Dublin Lennan/Lennon families |
| Lestrange |
| Letimer |
| Lewcy |
| Linahan |
| Linahan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Linch London (Irish connections) |
| Linchey London (Irish connections) |
| Linchy London (Irish connections) |
| Linehan |
| Linehan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Linnahan |
| Linnahan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Linnane Very extensive on Dublin Lennan/Lennon families |
| Linnehan |
| Linnehan Lenihan baptisms in Tournafulla, Limerick (archived) |
| Listin |
| Liston |
| Locklin |
| Locklin |
| Locklin |
| Locklin |
| Loftus |
| Loftus Wexford |
| Loftus |
| Loftus |
| Loghery |
| Lohery |
| Lonagan (archived) |
| Londergan (archived) |
| Londregan (archived) |
| Londrigan (archived) |
| Lonergan (archived) |
| Long Kilkenny/Nova Scotia |
| Longridge Hercules Langrishe |
| Lonican (archived) |
| Lonigan (archived) |
| Lonnergan (archived) |
| Lonregan (archived) |
| Looney |
| Loony |
| Lorcan Co. Galway |
| Loughery |
| Loughlan |
| Loughlan |
| Loughlan |
| Loughlan |
| Loughlin |
| Loughlin |
| Loughlin |
| Loughlin |
| Loughnan Wexford |
| Loughnane Wexford |
| Loughrey |
| Loughry |
| Louney |
| Louny |
| Loyden Tuam (archived) |
| Loydon Tuam (archived) |
| Luacey |
| Lucey |
| Lucy |
| Lundrigan (archived) |
| Luney |
| Luny |
| Luocy |
| Luoney |
| Luosey |
| Lydan Tuam (archived) |
| Lyden Tuam (archived) |
| Lydon Tuam (archived) |
| Lynch London (Irish connections) |
| Lynchy London (Irish connections) |
| Lyon |
| Lyons |
| Lysaght |
| Lyston |