When Humphrey Sumner Jennison was born on 12 June 1823, in Swanton, Franklin, Vermont, United States, his father, Joseph Sumner Jennison, was 32 and his mother, Theodora Barber, was 27. He married Calista J Olds in 1849, in Franklin, Vermont, United States. They were the parents of at least 1 son and 3 daughters. He lived in Laona Township, Winnebago, Illinois, United States for about 20 years. He died in 1893, in Winnebago, Illinois, United States, at the age of 70, and was buried in Durand, Winnebago, Illinois, United States.