My grandmother, Maggie Bellingham, witnessed his marriage. His brother, John Bellingham was presumably the John Bellingham who also witnessed it. (Al Luce database of Bann Valley Bellingham marriages.)
(BG - Thomas, Lavinia, Francis and Elizabeth Bellingham, aged 25, 24, blank and 21 respectively arrived in New York on the Anchoria from Londonderry on 23rd September 1904, to stay with the sister of Thomas, Mrs Wilson, sister in law of the other three, at 3 West 53rd Street, New York. Who is Mrs Wilson?)
He was living and working with my grandparents in Locust Valley, NY in 1918. Al Luce says, "I have just discovered a partial index to the World War I US Draft Registration cards (1917 - 1918). The index is part of the Ancestry.com subscription service. I did find a listing for a Thomas Gordon, native of Ireland, born: 29 Feb 1884, living with his wife, Margaret, in Locust Valley, NY and working as a farmer for an A. Burchard. Also registering from Locust Valley are: Thomas Bellingham (wife: Lavinia), working as a farmer for the same person and William J Bellingham (wife: no name given) born: Vow, No Ireland, working as an Insurance Broker. William registered in the first draft call on 5 Jun 1917 and the Thomases registered in the third call on 12 Sep 1918. Thomas Bellingham remained in the area through the 1920 and 1930 US Census returns and, in fact, there is still a Thomas Bellingham living in that area."