Claimants
- L'Estrange
- Lacey
- Lacy
- Lafayette
- Laffere
- Laheen
- Laidlaw
- Laing
- Lake
- Lalor
- Lalouette
- Lambe
- Lambert
- Lambert Barrett
- Lambert Orr
- Lambie
- Lamie
- Lancaster
- Landers
- Landy
- Lane
- Lane Joynt
- Lang
- Langan
- Langinger
- Langrishe
- Langron
- Lanigan
- Lanigan O'Keeffe
- Lansdowne
- Larken
- Larkin
- Larmour
- Larrissey
- Latimer
- Latta
- Lauder
- Laurence
- Lavery
- Law
- Law Smith
- Lawler
- Lawless
- Lawless Phelan
- Lawlor
- Lawrence
- Lawrenson
- Lawson
- Layzell
- Le Fevre
- Lea
- Leach
- Leacy
- Leahy
- Leary
- Leask
- Leavy
- Ledger
- Ledwidge
- Ledwith
- Lee
- Leech
- Leechman
- Lees
- Lees Coffey
- Leet
- Lefroy
- Leman
- Lemon
- Lenehan
- Lennon
- Lennox Robinson
- Lenox Conyngham
- Leonard
- Lett
- Lever
- Leveroni
- Levingston
- Levins
- Levinson
- Lewers Craig
- Lewis
- Lewis Crosby
- Liddane
- Lidington
- Lidwelll
- Lilburn
- Lilburn Henderson
- Liller
- Lilley
- Lindner
- Lindsay
- Lineham
- Linnane
- Lipsett
- Little
- Livingston Ramsay
- Llewellyn Lewis
- Lloyd
- Lloyd Tanner
- Lodge
- Logan
- Lombard
- Lombard Murphy
- Lonergan
- Long
- Longworth Dames
- Looney
- Loudon
- Loughlin
- Loughman
- Loughrea
- Loughrey
- Love
- Lowe
- Lowen
- Lowery
- Lowry
- Lowth
- Lucas
- Lumsden
- Lundon
- Lundy
- Lunney
- Lurring
- Lynam
- Lynch
- Lynch Staunton
- Lyne
- Lyon
- Lyons
- Lysaght
- Lysaght MacGowan