Monument to Major John S. Koster (1841-1921) in Port Leyden Cemetery on River Road and Main Street in Port Leyden, Lewis County, New York. Maj. Koster served in Company H, 21st Regiment Massachusetts Volunteer Infantry during the American Civil War. The 21st Massachusetts was part of Ferrero’s Brigade in the Union Army of the Potomac, which captured Burnside’s Bridge during the Battle of Antietam on September 17, 1862. It sustained 35 percent casualties at the Battle of Chantilly, which occurred during Confederate General Robert E. Lee’s pursuit of Union Maj. Gen. John Pope’s army after the Second Battle of Bull Run.
