Merrill was born on January 14, 1829, in Adams, New York, and came to what is now Milwaukee, Wisconsin, in 1837, where his father ran the Traveler's Inn at Walker's Point. Hiram worked in his father's shipyard, then headed west in 1849 for the California gold rush, where he sold water for hydraulic mining.[1] On October 20, 1856, he married Louise Ballard.[2] Merrill and his wife were Episcopalians. They had four children. He died on June 9, 1893.