Dr. Hill married Lizzie G. Vickery, daughter of the Hon. Peleg O. Vickery, on May 19, 1880. They had one child, Percy Vickery Hill, born on March 16, 1881. Lizzie died on April 10, 1893. Dr. Hill later married Laura Ligget, née Colman, widow of Hiriam S. Liggett, and daughter of former Secretary of Agriculture Norman Jay Coleman, on April 25, 1897. They had one daughter, Katharine Langdon Hill. Hill died in Eliot, Maine.
