On August 3, 1862, a nineteen-year-old Irish immigrant named Albert D. J. Cashier, enlisted in the 95th Illinois Infantry. Cashier fought in about forty battles and served until August of 1865.
It wasn’t until 1913 that Cashier, then living in the Quincy, Illinois, Soldiers’ Home, was discovered to actually be a woman. A 1915 deposition from a fellow soldier held by the National Archives found that the deception was extensive, aside from being the shortest person in the company, there was no other indication that Cashier was female.
Cashier died the following year in an insane asylum.
This image comes from the Illinois State Historical Library and the National Archives.