Harriet was the daughter of Lorin and Dolly (Fuller) Clark. Her mother died in 1865 in CT. Her father and family moved to IL by the 1870's. Her father second married, Lydia Fuller, her mother's sister in 1875. Harriet married James Graham Hamilton in 1878. They had a son, Wesley A. in 1878. James died in 1885. Wesley died in 1905 of TB at the age of 30.