Mills was first married to Sarah Hunt (1780–1802), a daughter of Dr. Ebenezer Hunt and Sarah ( Bradish) Hunt, on May 16, 1802. Sarah died a few months later on October 2, 1802. Mills later married Harriet Blake (1780–1871), a daughter of merchant Joseph Blake and Deborah ( Smith) Blake. With his second wife, Mills was the father of seven children, including: • Helen Sophia Mills (1806–1844), who married Hon.
Charles Phelps Huntington. • Elijah Hunt Mills Jr. (1810–1830), who died unmarried in
Charleston, South Carolina. • Charles Henry Mills (1813–1872), a merchant who married Anna Cabot Lowell
Dwight (1818–1880), a daughters of Edmund Dwight. • William Kilby Mills (1815–1855), an invalid for the last 20 years of his life; he died unmarried. • Harriette Blake Mills (1818–1892), who married Admiral
Charles Henry Davis. • George Francis Mills (1821–1829), who died young. Mills died on May 5, 1829, in Northampton, and was interred in the Bridge Street Cemetery. His widow died at Cambridge on February 9, 1871.
Descendants Through his daughter Harriette, he was a grandfather of Anna Cabot Mills Davis, who married U.S. Senator
Henry Cabot Lodge. One of their sons, poet
George Cabot Lodge, was the father of U.S. Senators
Henry Cabot Lodge Jr. and
John Davis Lodge. ==References==