A few things in your post that occur in my family... probably coicidence but thought I'd pass them along. They are: McMAHON, BOYLE, Ballybay and Rhode Island. I have female McMahon married to my MARTIN family men who were of southern County Monaghan. They immigrated to US in family groups starting in 1823. Initially in the greater Boston area, at least one grandson went to Pawtucket, RI by 1850. Bryan Martin was married in County Monaghan to Catherine McMAHON. he was born before 1800 & may have had a daughter as early as 1813. he emmigrated in 1826 to port of Boston. One of his son's was Dennis MARTIN, who became a fairly well-off currier in Pawtucket. His wife, though born in Scotland, was of Irish parents ... her name was Agnes (Lafferty) Martin. A daughter of ths couple married a Larkin son whose McGOUGH mother was of Ballybay. In a curious genealogical note witten in 1916 by this daughter, Catherine "Kate" (Martin) LARKIN (1854-1928) of Pawtucket, she writes of her mother, "Agnes Martin, wife of Dennis Martin and daughter of Dannel (sic) Lafferty and Agnes or Nancy the called her Boyle." Her handwritting is very clear ... but that passage in her genealogy journal has never made sense to me. She goes on to say, "Agnes Martin was born in Glasgow and mother was born in Tyrone, Ireland and Dannel, the father, was born in Antrim, Ireland" Sadly, this is the very last page of her 91 page journal. I suspect that something caused her to suddenly cease her research about 1917; she died in 1928.