Mabe: 

Hayston

McCortmick: 

Upton Castle

McGeoch: 

Stone Hall

Maelgwyn: 

Castle Malgwyn (Old)

Malefant (Malephant):

          Denant

          Marloes Court

          Upton Castle

Mannix: 

Eastwood

Marchant (Merchant): 

Penybenglog

Marloe: 

Marloes Court

Martel: 

Martel

Martin:

          Carne Coch

          Court (Cwrt), Egwlyswrw

          Hasguard

          Henllan, Rhoscrowther

          Lecha

          Lochmeilir

          Merrixton

          Penrhiw

          Pointz Castle (Cas Bwnsh)

          Summerton

          Trefellyn

          Trelewelyn

          Withybush

Martin (Lord Audley):

          Newport Castle

Martyn:

          Rickeston, Brawdy

          Tancredston

Marychurch: 

Norchard

Mason: 

Colby Lodge

Massy:

          Cottesmore

          Newgale

Mather: 

Stone Hall

Mathias:

          Bryn

          Castle Cenlas

          Castle Morris

          Castlebythe

          Fem Hill

          Frongoch

          Glastir

          Hayston

          Lamphey Court

          Little Milford

          Lochmeilir

          Lochturffin

          Llangwarren

          Rhos y Bayvil

          Trebrithin

          Tredrissi

          Trefayog

          Trewallter Lwyd

Meare: 

Martletwy House

Meares:

          Corston

          Eastington

          Haroldston Hall

          Kingston

          Llanion

          Narberth

          Pierston

          Talybont

Meilir: 

Lochmeilir

Melchior:

          Clyn Meredith

          Llandeilo

          Southfield

Mends: 

Bonville’s Court

Merchant (Marchant): 

Penybenglog

Meredith: 

Hook, Ambleston

Merriman: 

Coedcanlas

Merydith: 

Carswell

Meyler:

          Cerbyd

          Cilciffeth

          Howelston

          Tredduog

          Treleweyn

          Trewallterwen

Meyrick:

          Bangeston St. Mary Pembroke

          Bush

          Castleton

          Denant

          Fleet

          Gumphreston

          Hasguard

          Llanion

          Norchard

          Paterchurch

          Simpston

          Wedlock

Michalski: 

Llangolman

Miles:

          Helygant

          Hendre, Meline

          Longhook

Milford, Lord see Philipps

Mirehouse:

          Angle

          Bangeston, Angle

          Brownslade

          Eastington

Moody: 

Thorne

Moore:

          Glanduad (Glanduad Fawr)

          Musselwick (Muslick)

          Penrhiw

Mordaunt:

          Hilton

          Scovaston

Moreiddig Warwyn of Breconshire,

Morgan:

          Anastaslade

          Blaenbylan

          Brynaeron

          Carnachen Wen

          Cartlett Llanrhian

          Cilfowir (Cilfowyr)

          Cilgadfarch

          Cilwendeg

          Coedllwyd

          Dolpwll

          Ffynnonau Bychan (later Ffynnone)

          Gilfachwrnell

          Haythog

          Hoaten

          Johnston (Hall)

          Llwyn Bedw

          Parsele

          Penbedw

          Pencelli Fawr

          Rhydgarnwen

          Tregaman

          Tregroes

          Trenewydd

          Trerickert

          Wernddofn

          Whitechurch

Morgan-Richardson:

          Morgenau

          Rhosygilwen

Morris:

          Bachendre

          Blaiddbwll

          Castle Villa (Caswilia)

          Cerbyd

          Clynsaithman

          Cwm Cerwyn

          Ffynnonau Bychan (later Ffynnone)

          Gilfachwrnell

          Hayscastle (Caslai)

          Howelston

          Llanreithan

          Llether

          Llwyn Bedw

          Nantylladron

          Park y Pratt

          Parsele

          Pentre Ithel

          Plâs Iwerill

          Rhosmoeled

          St. Elvis

          Tregaman

Morrison: 

Portclew

Morse:

          Boulston

          Dudwell

          Graig

          Parsele

          Penallt Cych

          Rinaston

          Trerhos

Mortimer:

          Castle Malgwyn (Old)

          Cilfowir (Cilfowyr)

          Court (Cwrt), Llanllawer

          Garn

          Llanwnwr

          Penysgwarn

          Trehowel

          Trewellwell

          Wolfsdale

Morton: 

Heathfield (Lodge)

Mossylwyke: 

Folkeston

Munster, Count: 

Castle Malgwyn (Old)