Emma Dupuy was born around 1838 in Virginia to James Dupuy. Her father was a merchant who owned $200 of real estate, and he died around 1855. By the early 1860s, she was living in Farmington, Missouri. She married Ellis Plumer Cayce in St. Clair, Missouri, on October 6, 1862, and they had at least three children: Lillian, born around 1870; Elsie, born around 1872; and Paul, born around 1876. They remained in Farmington, and her husband worked as a dry goods merchant. By 1870, they owned $2,500 of real estate and $3,000 of personal property. They moved to Iron Mountain, Missouri, sometime in the 1870s, and she died in 1895.