Unfortunately not much is known of the Meehan family, but it is believed they came from the townland of Derrygirraun, Cootehall (Ardcarne) in Co. Roscommon.
I wonder if 'unknown' was related to Thomas and Patrick Mughan (a misspelling of Meehan, perhaps?) in the Tithe Applotment Books from 1834 for the townland of Glora (nowadays spelled as Glooria) which lies adjacent to Derrygirraun. A Charles Meehan and a Patrick Meehan are listed in Griffith's Valuation from the 1850s as occupiers in Derrygirraun so it is possible that some or all of the above were related to 'unknown'.
I have been told of a Stewart Meehan and a Paddy Meehan who lived in Derrygirraune (in separate properties) in the 1ast century. Research has shown that Stewart was born in 1902 to Bernard Meehan and Frances McLoughlin who had six other children that we know of: Charles, Patrick, Florence, Frances, Mary Ellen and Maggie. Charles became a Holy Ghost Father and was working in Nigeria in the 1930s. It appears he left the priesthood in the 1940s and married. He died in California in 1967.
Stewart himself died in 1969. His parental grandparents were Peter Meehan (c.1814-1888) and Bridget (c.1818-1902) whose surname is unknown. I have also been told Stewart's family was connected to an Appleby family. This is likely due to the marriage in 1902 of James Appleby and Bridget Meehan, both from [what looks like] 'Tiernameenthera' (could this be part of either Derrygirraun or Glooria?) in Cootehall. Bridget was a daughter of Pat Meehan and Ellen McLean of Glooria and James was a son of Thomas Appleby and Bridget Feehily/Foley, also of Glooria.
Another family with Glooria/Derrygirraun connections is that of Thomas Meehan of Glooria or Derrygirraun who married Mary Shivnan. They had a son named Thomas (born 1867 in Glooria) and a daughter, Sarah (born 1871). Thomas (junior) married Julia Anne Farrell in 1902 and they had a son, Thomas Joseph, in 1903. Thomas Joseph, who was possibly an only child, married Mary K. Holland from Ballyfermoyle, Boyle, Co. Roscommon in 1938 and there are descendants of theirs still living in Derrygirraun. However, I have been unable to connect this family with that of Stewart or 'unknown' Meehan above. Any help in proving - or disproving - a connection would be very welcome. Please email Helen@HelensFamilyTrees.com with any information. Thank you in advance.
Note: The Meehan surname comes from the Irish "Ó Miadhacháin", from the word "miadhach" meaning "honourable". Historically, the most notable family of the name was an offshoot of the MacCarthys of the kingdom of Desmond in south Munster. However, as early as the eleventh century, they migrated north to Co. Leitrim, and from there they spread slowly into the adjoining counties. The name is now common throughout east Connacht and counties Donegal and Fermanagh. There also appears to have been a separate family which adopted the surname in the Clare/Galway region where the name is also numerous. In Co. Monaghan, and there alone, Ó Miadhacháin has been anglicised as "Meegan". In Co. Sligo the name "Ó Maotháin" has sometimes been anglicised as Meehan, while in east Ulster, the name "MacMeekin", from the Irish "Mac Miadhacháin", has also sometimes become Meehan.