When Nathanial Seymour was born on 24 August 1763, in West Hartford, Hartford, Connecticut, United States, his father, John Seymour, was 36 and his mother, Lydia Wadsworth, was 32. He married Sarah Kellogg on 18 January 1790, in West Hartford, Hartford, Connecticut, United States. They were the parents of at least 4 sons and 1 daughter. He died on 26 February 1849, in his hometown, at the age of 85, and was buried in West Hartford, Hartford, Connecticut, United States.