
They were called “Galvanized Yankees,” and were recruited at prisoner of war camps during the winter of 1864-65 to fill in behind the cavalry and guard the travel routes during the campaign against the Plains Indians under generals John Pope and Grenville Dodge. They were formed into two infantry regiments under federal officers. They joined another regiment, the First U.S. Volunteers recruited from prison camps in Virginia the previous summer. Ultimately there were six regiments of Galvanized Yankees who performed credible work policing the Plains during the last days of the Civil War.
Most volunteered for duty in the West to escape the horrors of prison camp life and although they became “Billy Yanks” in their adopted uniform they remained “Johnny Rebs” in their hearts. Actually there were Union troops who switched to Confederate gray for the similar reasons
Author Dee Brown wrote a book about these volunteers titled, “Galvanized Yankees.”