George Hamilton Mowry was born around 1842 in Pennsylvania to John Mowry. His father was a carpenter who owned $2,000 of real estate and $335 of personal property by 1860. Mowry grew up and attended school in Lurgan, Pennsylvania, and by 1860, he was working as a coachmaker. He married Elmira Coon on October 3, 1867, and their daughter Sarah was born around 1869. They lived in Newville, Pennsylvania, and by 1870, he owned $1,500 of real estate. He died sometime after 1880.