Thomas Green Barr, (b. ca. 1821-d.1 881) was the son of William Barr who arrived in Saint John, New Brunswick, from Glasgow, Scotland. It is believed William Barr married Mary Green on 9 December 1816. Thomas carried on the ironmongery business begun by his father and grandfather. Thomas Barr was appointed surveyor of lumber for the City of Saint John in 1847. He was a lieutenant in the 2nd Battalion of the Saint John City Light Infantry in 1865 and was Captain in 1867. Thomas was a member of the Saint Andrew's Society.

Thomas was married twice. First, to Maria Louisa Haviland (b. 3 February 1820-d. 22 September 1855) on 11 January 1843. They had 3 children: William Haviland (b. ca. 1846), Maria Louisa, (b. ca. 1847) and Thomas Edward (b. ca. 1850). Thomas remarried on 11 March 1857 to Jane M. Condle (b. ca. 1847-d. 22 September 1922 at age 75) of Greenwich, Kings County, N.B. Their children were: Frederick, Annie, Edith and Elizabeth. Frederick became a travelling salesman and was married to Ida Harding. They had a daughter, Jean.