Aaron Harlan enlisted on July 20, 1861, as the commissary sergeant of the 1st Northeast Missouri Home Guard Infantry. In February 1862 the 1st and 2nd Northeast Missouri Regiments were consolidated to form the 21st Missouri Infantry, and Harlan became the regimental commissary sergeant. On January 1, 1864, he was removed as regimental commissary sergeant at his request, reduced in rank to private, and assigned to Company G.

The 21st Missouri Infantry saw action at Shiloh, Iuka, Corinth, Pleasant Hill, Tupelo, Nashville, and Fort Blakely.

He was mustered out of the service on December 5, 1864, at Nashville, Tennessee. Harlan died in 1911.

Carte-de-Visite by Unknown Photographer.

Image Courtesy Wilson’s Creek National Battlefield; WICR 11620