My wife and visited the B & O Railroad museum in nearby Ellicott City, Maryland which was on the route from Baltimore to points west. They have a very interesting exhibit relating to the railroad in the Civil War. When Harpers Ferry was captured in September of 1862, almost 12,000 Union troops were captured and paroled. There was a brief display about what happened to some of these guys marching south to Camp Parole near Annapolis under some sort of escort ( this whole idea of being paroled and promising not to fight until exchanged fascinates me). Some of these guys ended up in Ellicott Mills (the old name for Ellicott City) and did some bar hopping before the ended up being rousted and sent south.
But what is fascinating is that 8000 of these guys ended up in Camp Douglas in Chicago to await being exchanged. And they had to endure almost the same conditions as Confederate prisoners. Here is the Wikipedia entry regarding this.
Union soldiers who were paroled after their capture by Confederate Lieutenant General Thomas J. “Stonewall” Jackson at the Battle of Harpers Ferry, Virginia (later West Virginia) on September 15, 1862 were sent to Camp Douglas for temporary detention. Under the terms of the prisoner cartel, they had to await formal exchange before they could leave the camp. These 8,000 paroled Union soldiers began to arrive at Camp Douglas on September 28, 1862. Brigadier General Daniel Tyler relieved Colonel Tucker of command of the camp. Under Tyler’s command these Union soldiers had to live under similar conditions to those endured by the Confederate prisoners from Fort Donelson. In fact, the conditions were worse because the camp had become filthy and even more run down during its occupancy by the prisoners. The paroled soldiers were fortunate to have only about a two–month stay. They were able to tolerate the conditions somewhat better than the previous Confederate prisoners could because the Union parolees were more warmly dressed and in better physical condition. The damp conditions and bad food still took their toll on the parolees. By November, forty soldiers of the 126th New York Volunteer Infantry Regiment were dead and about another sixty were ill with fevers.
Under these oppressive conditions, the Union Army parolees soon became mutinous, set fires and made many attempted escapes. On October 23, 1862, General Tyler brought in regular U.S. troops to stop parolee riots. Secretary of War Edwin Stanton also ordered Tyler to relax his strict discipline which helped calm the parolees. Most of the prisoner of war exchanges between the Union and Confederate armies under the cartel were completed by the end of November, 1862 All the parolees left the camp by the end of that month except for Colonel Daniel Cameron and his 65th Illinois Volunteer Infantry Regiment who were held until April 19, 1863 and put to work as guards. Thirty–five men of this regiment also had died of disease at the camp during their confinement.