Andrew Jackson VanHorn was born around 1834 in Ohio to Samuel VanHorn and Isabelle Minard. His father was a farmer. He grew up and attended school in Wood County, Ohio. He married Mary Dealy in the late 1850s, and they had at least two children: Samuel, born around 1858; and Jane, born around 1859. They moved to Fort Wayne, Indiana, in the late 1850s, and VanHorn worked as a carpenter. By 1860, they owned $200 of real estate and $50 of personal property. He enlisted in the Union army on July 29, 1862, and mustered in as a private in Company C of the 74th Indiana Infantry. Army officials transferred him to the 2nd Veteran Reserve Corps on September 7, 1863. VanHorn returned to Indiana after the war. His wife Mary died sometime in the 1860s, and he married Clara L. Dean on September 23, 1870. They had seven children, including Frank, who was born around 1891. They eventually moved to Lima, Ohio, and VanHorn died sometime after 1920.