Horatio is listed in the 1855 New York census with his parents as Horatio B. Fenton (16).
He is listed as crew on the whaling ship Jeanette out of New Bedford, MA in 1858, at the age of 19.
He was married and living in Ellicott when he registered for the Civil War Draft on 1 Jul 1863.
In 1865 he was living in Ellicott, NY with his wife Mary E. Johnson (21, Chautauqua Co, NY), along with her mother Elizabeth Johnson (58) and brother William P. Johnson (26).
On May 18, 1866 he requested a Pardon for his one year prison sentence for Grand Larceny conviction of June 1865. It was granted and on Oct 22nd, he also requested that his citizenship rights be restored (which was apparently granted as well, since these documents are listed in the Executive Orders for New York state.)
In 1868 he registered to vote in Santa Cruz, CA, and by 1870 he and Mary were living in Curry Co, Oregon where he worked as a laborer.