When Julius Marcellus Kelsey was born on 21 July 1836, in Tunbridge, Orange, Vermont, United States, his father, James Kelsey, was 35 and his mother, Catherine Smith, was 29. He married Susan Berg on 26 March 1868, in Vermont, United States. They were the parents of at least 1 son and 1 daughter. He lived in Stockholm, St. Lawrence, New York, United States for about 10 years and New York, United States in 1870. He died on 3 November 1905, at the age of 69, and was buried in Buckton, Stockholm, St. Lawrence, New York, United States.