Joseph Latshaw Horr, son of Leonard and Harriet Latshaw Horr, was born in Dundas, Ontario, Canada, on April 13, 1838. While in his teens, he moved with his parents to Dubuque, Iowa. At the outbreak of the Civil War, he enlisted in the 13th Regiment, U. S. Infantry (Regular Army). He was quickly made first sergeant of Company C, First Battalion. He later rose to the rank of captain and was eventually brevetted a major. He was wounded at Vicksburg in May 1863, and was assigned to recruiting and mustering duty in Illinois, Michigan, Missouri, and IowaIllinois. Following the Civil War, he was ordered with his regiment to the frontier to participate in the American Indian Wars, spending much of this time in Montana. He married Elizabeth R. Ogilby (1843-1915) in 1870; the couple would have four children. Soon afterward, Horr resigned his commission and returned to Dubuque, where he engaged in farming and stock-raising. Joseph L. Horr died in Chicago in 1914.

The 13th U. S. Infantry was organized at Jefferson Barracks, Missouri in October, 1861. The regiment saw duty at Memphis until November 1862, then participated in Grant's Central Mississippi Campaign and Sherman's Yazoo Expedition. The regiment continued to serve in Mississippi and Arkansas and participated in the siege of Vicksburg before being moved to Tennessee, where it participated in the Battle of Chattanooga. The 13th served as guard at Sherman's headquarters from April to July, 1865, then was moved to the frontier to participate in the American Indian Wars.