When William Henry Trevithick was born on 22 February 1840, in Gwennap, Cornwall, England, United Kingdom, his father, William Trevithick, was 25 and his mother, Johanna Youlton, was 23. He married Mary Jeffery on 2 April 1864. They were the parents of at least 3 sons. He lived in Central City, Gilpin, Colorado, United States in 1880 and Laurium, Houghton, Michigan, United States in 1900. In 1895, at the age of 55, his occupation is listed as miner in Marquette, Michigan, United States. He died on 23 May 1910, in Calumet, Houghton, Michigan, United States, at the age of 70, and was buried in Lakeview Cemetery, Houghton, Michigan, United States.