The York U.S. Army Hospital was one of Pennsylvania's largest military hospitals during the American Civil War. It was established in York, Pennsylvania, to treat wounded and sick soldiers of the Union army. The hospital was established in July 1862 on Penn Common, a large level, grassy area just south of downtown York. The sprawling facility consisted of numerous barracks, infirmaries, offices, and support facilities such as laundries, stables, and a mortuary. Among the early patients were hundreds of wounded men transported to York following the September 17, 1862, Battle of Antietam.