When Thomas Montgomery was born on 29 February 1836, in Madison, Monroe, Missouri, United States, his father, Jonathan Lee Montgomery, was 28 and his mother, Mary Anderson Eagle, was 28. He married Julia Ann Rucker on 9 November 1855, in Franklin, Howard, Missouri, United States. They were the parents of at least 2 daughters. He died on 20 June 1892, in Ashtabula, Ashtabula, Ohio, United States, at the age of 56, and was buried in Ashtabula, Ashtabula, Ohio, United States.
English, Scottish, and northern Irish (of Norman origin): habitational name from Sainte-Foy-de-Montgomery and Saint-Germain-de-Montgomery (Calvados). In Ireland this surname was present in the medieval period, died out, and was then reintroduced from Scotland in the 17th century. It has been Gaelicized in Ireland as Mac Iomaire and in Scotland as Mac Gumaraid.