Though Palmer’s Quaker upbringing dissuaded him from violence, his sense of duty and loyalty to the Union cause led him to join the army. He became captain of a cavalry troop after showing valor in the Battle of Bull Run, and he participated in both the Shiloh and Nashville campaigns. In 1862 he was asked to lead the Fifteenth Pennsylvania Cavalry, which fought at the Battle of Antietam and helped defeat Robert E. Lee’s Army of Northern Virginia. The day after the battle General McClellan recruited him as a spy for duty behind enemy lines, where he was captured and held prisoner until 1863. After his release he returned to his post and, after the surrender of Confederate General Joseph E. Johnston, was given command of the troops that were sent to pursue Confederate President Jefferson Davis himself. He retired from the military at 29 years old after receiving the Congressional Medal of Honor and earning the rank of Brigadier-General. It was then that he was finally able to return to his career in the railroad industry.
As the Civil War came to an end, William Jackson Palmer moved west to begin surveying and planning, what he believed, was to be a new Industrial Revolution in the West. Palmer and his associates formed the Denver and Rio Grande Railway Company, and purchased thousands of acres of land in Colorado for the development of railroads, coal mines, and cities. Palmer and his associates approved a plan to consolidate their non-railroad ventures into a single corporation, the Colorado Coal and Iron Company, which merged with John C. Osgood's Colorado Fuel Company in 1892 to form the Colorado Fuel and Iron Company (CF&I), instantly becoming the largest employer and private landowner in Colorado. CF&I went on to control nearly all Southern Colorado coal mines between 1872 and 1982, and operated the largest steelworks plant west of the Mississippi River in Pueblo, Colorado.
Palmer and his associates also laid out plans for the cities of Manitou Springs, Colorado Springs, and the town of Bessemer, which is now part of the city of Pueblo. They built millions of dollars worth of roads, parks, and playgrounds, and founded Colorado College in Colorado Springs. General Palmer also built Glen Eyre, an English Tudor-style castle with seventeen guest rooms, four meeting rooms, and two dining rooms, which has since become a famous Colorado Springs landmark.
William Jackson Palmer http://heritagewest.coalliance.org/items/show/72892
 Walter Hines Page, The World’s Work: A History of our Time, Vol. 15 (New York: Doubleday, Page & Company, 1908), 9899. All factual information to this point comes from this book.
 Thomas G. Andrews, Killing for Coal: Americas Deadliest Labor War (Cambridge: Harvard University Press, 2008), 43.
 H. Lee Scamehorn, Mill & Mine: The CF&I in the Twentieth Century (Lincoln: University of Nebraska Press, 1992), 10.
 Page, 9901.
 The Official Website of Glen Eyrie: http://www.gleneyrie.org/