Here are the details going back from my father:
My father: Thomas McTiernan (deceased)-m- Elizabeth McFadeyn Thomas' brother Jack (John) [also deceased] and sister Rita (Margaret).
James Patrick McTiernan -m- Mary Dale Henderson on 24/10/1928 (DOB: 18.09.1899, born in Glasgow)
Frank and his family (Frank and Joe) live in New Jersey and Betty stays in Long Island (they have been there for over 40 years).
Joseph's son Joe lives with his family in Washington, Co Durham.
Betty has never married and Margaret and her husband didn't have any children.
James Patrick McTiernan -m- Sarah Jane Haran on 21.01.1897 in Glasgow
only known brother or sister: Joseph
Patrick McTiernan -m- Mary Finnigan (2nd wife?) (First wife Mary McTiernan??) Patrick died 26.6.1890
Only known brother/sister: James
Great/Great/Great Grandfather/Mother: Andrew McTiernan -m- Ann Gordon, (Farmer)
I came to a halt with Andrew McTiernan. From verbal family history, the family lived in Manorhamilton, with James Patrick (Great Grandfather) probably the first to come over to Scotland from Ireland.
For further interest, there are around nine McTiernans listed in the Glasgow telephone directory living in the Kilsyth area of Scotland (east of Glasgow) - probably all related to each other by their addresses but am not sure how closely I am related to them. I intend to try and do more detailed research from the limited details I have and will gladly pass this on to you.
Hope this is of interest and I look forward to hearing from you, as there don't appear to be too many of us McTiernans around!