John DuMaresq was born on May 8, 1808, in St. Saviors on the island of Guernsey in the English Channel. He immigrated to America on March 29, 1836, and settled in Fulton County, Ohio. He married Margaret Coates MacKay on March 9, 1837, and they had at least six children, including John, who was born around 1839. He worked as a farmer, and in 1860, he owned 120 acres of land worth $1,800. That year, he produced 80 bushels of wheat and 100 bushels of corn.
Twenty years later, he owned $7,000 of real estate, and he produced 15 tons of hay, 500 pounds of butter, 200 bushels of wheat, 500 bushels of corn, and 130 bushels of oats. According to his children, he was a “faithful member of the Episcopalean [sic] church” and a “kind husband, a good father and a faithful friend.” His wife died on April 11, 1889, and he followed on September 15, 1892.