Campaigns of the First Ohio
Battery L was mustered in Cincinnati, Ohio at Camp Dennison on October 8th 1861 for a three year enlistment. They were present for the Battle of Winchester, Battle of Fredericksburg, Battle of Chancellorsville, Battle of Gettysburg, Battle of Opequan, and the Battle of Cedar Creek. They returned to Columbus, Ohio in 1865.
Although the location of the his battery are known, Marsh was not specifically confirmed at all of these sights and spent at least some period of time in a hospital during the war.