Horatio Nelson Fenn (b. 1798, d. 1871) was born in Plymouth, Connecticut, in March 1798 and spent a few years of his youth with his father in New Haven, Connecticut. For a portion of his residency in New Haven he worked as a clerk in a drugstore. Later he moved to Rochester, New York, where he studied medicine with Frederick Fanning Backus (Yale College 1813; Doctor of Medicine 1816), and also worked in Backus’s drugstore.

While in Rochester from 1818 to 1819, Fenn investigated the botany of the region. Probably as a result of his association with Backus, Fenn returned to New Haven in 1822 to study at the Yale College Medical Institute. In those days, the medical program began at the end of October and continued through March, with each professor delivering 80 to 100 lectures. Only one term of lectures was required, and Fenn graduated in March 1823.

After finishing at Yale, Fenn returned to upstate New York to practice medicine in Geneseo. In 1826, he joined Albert Backus in a venture to manufacture glass in Petersboro, New York. In 1830 Fenn returned to Rochester to practice medicine and dentistry, with the latter eventually becoming his primary profession. In his early practice, he fashioned false teeth from ivory, but was using porcelain by 1834.

Fenn continued to be an innovator in his community. He compiled the 1856 map of Rochester as it was in 1820. Fenn also claimed to have set up the first soda apparatus in this area, the first mechanical ice house, and to have been among the first in the area to use the daguerreotype and electrotyping processes. He was also a strong proponent of public education.

Fenn and his wife Henrietta F. Hughes of Hagerstown, Maryland, were married in 1883 and had 4 children, 2 of whom survived into adulthood: Robert Hughes Fenn (b. 1834, d. 1913) and Samuel Purviance Fenn (b. 1835, d. 1921). After suffering with rheumatism for several years, Horatio Fenn died on April 10, 1871.