American Civil War Medal of Honor Recipient. He received the award on June 30, 1892 for his actions as a major in the US Army Volunteers at the Battle of Resaca in Georgia on May 15, 1864. After graduating from the College of the City of New York in 1860, he enrolled at Columbia College Law School. Following the outbreak of the American Civil War on April 12, 1861, he enlisted in the New York 7th Regiment as a private and soon afterward he recruited a company that joined the 2nd Regiment of the 73rd New York Infantry Fire Zouaves. After attaining the rank of 1st lieutenant, he served as a staff officer to Union Generals Nelson Green and John Pope. At the 2nd Battle of Bull Run on August 29, 1862,, he was captured and briefly held at Libby Prison in Richmond, Virginia before being paroled a month later. He was then promoted to the rank of captain and mustered into the US Volunteers as a major and later became aide-de-camp to Union Generals Daniel Sickles, Daniel Butterfield, David Gregg, and George Crook, and during the course of his military career, he was present at the Battles of Fredericksburg, Chancellorsville, Gettysburg, Chattanooga, and Petersburg. It was during General Sherman's March Through Georgia Campaign where, at the Battle of Resaca, his course of action would win him the Medal of Honor. Following the war's conclusion, he received brevet promotions up to the rank of brigadier general and he retired in April 1866, then returned to New York City to finished his law degree and opened a law practice. He later wrote several books on the Civil War, including "The Last Hours of Sheridan's Cavalry" and "Two Days of War; a Gettysburg Narrative. and Other Excursions." He died at the age of 70. His Medal of Honor citation reads: "The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Major & Aide-de-Camp Henry Edwin Tremain, United States Army, for extraordinary heroism on 15 May 1864, while serving with U.S. Volunteers, in action at Resaca, Georgia. Major Tremain voluntarily rode between the lines while two brigades of Union troops were firing into each other and stopped the firing."