Margaret was born about 1750 based on the
      number of children she had and estimate of their ages based on her
      husband's will.   Her birth name is unknown. However, I
      suggest with evidence below that her last name was 
Murphy. 
      If that is true then her parents were
 John Murphy and maybe 
Margaret
        LNU
      
      Our 
Margaret married
 Robert McMaster about
      1769.  Their first child was born about 1770. 
      
      On Sept 14, 1793 
John Murphy wrote a will.  It was
      proved Sept 12, 1794, and presented by his wife 
Margaret
        Murphy.
 Cecil County Will Abstracts by John McCory, 
        Will number 206 on page 347.    I have not
      seen the will only the Abstract, so can't interpret beyond info
      Mr. McCory recorded.    In the will he mentions
      wife, unnamed there, wife's son
 Aaron Wark, but she is
      named as presenting the will.  Thus I assume that 
Margaret
        Murphy had been previously married to a
 Mr.
        Wark.   the will goes on to name 
John Brown,
      (no kinship given), 
 Margaret McMaster - wife of
        Robert McMaster, other"eldest daughters" not
      named.....etc   
Robert McMaster was one of his
      executors and a witness was
 Samuel McMaster.
      
      To me, it seems clear that 
Margaret McMaster was the
      daughter of 
John Murphy and very possibly his wife 
Margaret.
      
      
The McMaster Family of Cecil County by Gary Burns list
      with a fair amount of detail the children of 
Robert and
        Margaret McMaster:  they are,
      1.  
Mary McMaster  born about 1770  wed 
David
        Archibald in 1790. 
      2.  
Jane McMaster born about 1773  wed 
John
        Fisher in 1794.
      3. 
 Sarah "Sally" McMaster born c 1778 never married,
      had one child 
James Galbraith.
      4.  
Robert McMaster II born in 1782, wed 
Martha
        Taggart in 1822
      5. 
 Samuel McMaster don't know when he was born,
        but he was a witness to his grandfather, John Murhpy's,
      will.   I would think he would need be at least 15
      or 16,  so he was probably born   before
 Robert
        II.  However, it makes sense for eldest son to be named
      after his father.   
Samuel never married. 
      He died in 1821.  
      6. 
 Keziah McMaster born about 1795, wed 
Thomas
        Fisher about 1820 
      7.  
Andrew McMaster I
      believe to have been born about 1888.  He wed 
Ann Dobbin about 1813. When 
Ann
      died he married widow 
Margaret Watson
      about 1826.  He died between 1840 - 1850. 
      8.  
Rebecca McMaster born about 1800.  She was
      mentioned in her father's will, but believed to have died before
      1821.  
      
      These dates were best guesses by Mr. Burns.  Actually he had
      put 
Andrew born 1781.  I have doubts about that
      date.  
      
      In 1785
 Robert McMaster patented property in Susquehanna
      Manor.  It was just over 210 acres and was named 
        McMaster's Delight.  The family lived there for many
      generations.   It was near present day Woodlawn, though
      at the time it was called Battle Swamp.   
      
      
Census Cecil County North Susquehanna Hundred 1790 has the
      family listed: the names given are my guesses and they truly are
      just guesses except for the 2 
Roberts. 
      Robert McMaster
      3 males > 16 
 
      2 males < 16 
      8 females      
      no slaves
      
      The 
1810 Cecil County Census page 62, Northern Township (I've
      not found them on 1800 Census).
      
 Robert McMaster      
                 
          
      1 male < 10 
      1 male 16-25        
                  2 females
      16- 25
      3 males 26-45        
                 1 female 26-45
      1 male > 45   
  Robert    
         1 female >45       
        Margaret
      
       I cannot put in names, but I believe it very likely that in
      both census grown children were living with 
Robert and Margaret
      with their families.
      
      In 1793 
Robert and 
Margaret McMaster signed the 
Oath
        of Allegiance, becoming Naturalized Citizens on Feb.
      1793.  It stated 
Robert's birthplace was 
Ireland,
      
Margaret was not given.It also stated they lived in
      Battleswamp, Maryland.
      
      Robert McMaster died in 1816.  His will had been written in
      1812 and Margaret was named as his wife.  
Cecil County
        Clerk of Wills, will book GG 7, page 131. So it is believed
      she was still alive in 1816.  I believe it very possible that
      she continued to live at McMaster's Delight with first 
Samuel
      and then 
Robert Jr.  
      
       We do not know when 
Margaret Murphy McMaster died,
      or where either are buried.  
      
      
      .