Union XII Corps

      General Joseph K. Mansfield                      General Henry Warner Slocum                General Alpheus S. Williams                     General John W. Geary


Major General Henry Warner Slocum

Major General Henry Warner Slocum, U.S.A., Commander Twelfth Army Corps, Gettysburg, Pennsylvania, Commander Fourteenth and Twentieth Army Corps, Commander, Army of Georgia, Sherman’s March to the Sea (left wing)

Henry Warner Slocum could be remembered in history for so much: he was a successful politician, a flourishing business man, railroad tycoon, colonel, brigadier, major general, corps commander, and even army commander. Some individuals spend their entire lives pursuing just one of these titles. Slocum played an important role fighting in the Civil War eastern theater from Bull Run to Gettysburg, was post commander at Vicksburg, and then served in nearly every battle in the western theater from the capture of Atlanta to Johnston's surrender" (Melton, 2007). Slocum served at Bull Run, the Peninsula, South Mountain, Antietam, Chancellorsville, Harper's Ferry, Gettysburg, Tennessee, Vicksburg and Atlanta. General Slocum served as Sherman's left wing commander in the famous "March to the Sea." Slocum's Army of Georgia fought in the battles of Bentonville and Bennett Place.

In the course of the March to the Sea, Sherman's army liberated hundreds of thousands of slaves. Slaves escaped from their plantations and fell in behind the Union Army.

According to Brian C. Melton (2007), Slocum is the forgotten general of the Civil War, largely remembered for his leadership in the battle of Gettysburg.

There are a number of reasons why General Slocum has been largely forgotten and ignored. One reason is that after the war, Slocum defected to the Democratic Party and lost a significant election in upstate New York. There he was vilified for this. Another reason is that, unlike other Civil War generals, Slocum did not write a memoir. Further, Slocum did not pursue a military career after the war. Slocum was modest about his military service and hardly promoted himself.

Slocum's official documents and reports survive in the Civil War records of the National Archives. Only a few personal letters exist in libraries and archives throughout the country. Few personal papers exist in New York or other places where he originally resided. There are three biographies of General Slocum.

SLOCUM, Henry Warner, soldier, b. in Delphi, Onondaga co., N. Y., 24 Sept., 1827. He was graduated at the U. S. military academy in 1852, appointed 2d lieutenant in the 1st artillery, and ordered to Florida the same year. He was promoted 1st lieutenant in 1855, but resigned in October, 1856, and, returning to New York, engaged in the practice of law at Syracuse, and was a member of the legislature in 1859. At the opening of the civil war he tendered his services, and on 21 May, 1861, was appointed colonel of the 27th New York volunteers. He commanded this regiment at the battle of Bull Run on 21 July, where he was severely wounded, on 9 Aug. was commissioned brigadier-general of volunteers, and was assigned to the command of a brigade in Gen. William B. Franklin's division of the Army of the Potomac. In the Virginia peninsula campaign of 1862 he was engaged in the siege of Yorktown and the action at West Point, Va., and succeeded to the command of the division on 15 May, on Franklin's assignment to the 6th corps. At the battle of Gaines's Mills, 27 June, he was sent with his division to re-enforce Gen. Fitz-John Porter, who was then severely pressed by the enemy, and rendered important service, as he did also at the battles of Glendale and Malvern Hill, his division occupying the right of the main line at both engagements. He was promoted to the rank of major-general of volunteers, 4 July, 1862, engaged in the second battle of Bull Run, at South Mountain, and at Antietam, and in October was assigned to the command of the 12th army corps. In the battles of Fredericksburg, Chancellorsville, and Gettysburg he took an active part. At Gettysburg he commanded the right wing of the army, and contributed largely to the National victory. Having been transferred with his corps to the west, he served in the Department of the Cumberland till April, 1864, when, his corps being consolidated with the 11th, he was assigned to a division and the command of the district of Vicksburg. In August, 1864, he succeeded Gen. Joseph Hooker in the command of the 20th corps, which was the first body of troops to occupy Atlanta, Ga., on 2 Sept. In Sherman's march to the sea and invasion of the Carolinas, he held command of the left wing of the army, and participated in all its engagements from the departure from Atlanta till the surrender of Gen. Joseph E. Johnston at Durham station, N. C. In September, 1865, Gen. Slocum resigned from the army and resumed the practice of law in Brooklyn, N. Y. In 1866 he declined the appointment of colonel of infantry in the regular army. In 1865 he was the unsuccessful candidate of the Democrats for secretary of state of New York, in 1808 he was chosen a presidential elector, and he was elected to congress the same year, and reelected in 1870. In 1876 he was elected president of the board of city works, Brooklyn, which post he afterward resigned, and in 1884 he was again elected to congress. He was one of the commissioners of the Brooklyn bridge, and was in favor of making it free to the public.”

Source: Wilson, James Grant, & Fiske, John (Eds.). Appleton's Cyclopaedia of American Biography. New York: Appleton, 1888, 1915.

Cullum, George W., Biographical Register of the Officers and Graduates of the U.S. Military Academy (3 vols.). Boston and New York, 1891.

Eicher, John H., and David J. Eicher. Civil War High Commands. Stanford, CA: Stanford University Press, 2001.

U.S. Congress, Biographical Directory of The United States Congress, 1774–2005. Washington, DC: GPO, 2005.

U.S. War Department. The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. 128 vols. Washington, DC: GPO, 1881-1901. Series 1.

Warner, Ezra J. Generals in Blue: Lives of the Union Commanders. Baton Rouge: Louisiana State University Press, 1964.

Life of General Slocum

Source: Fox, William F. In Memoriam: Henry Warner Slocum. Albany, NY: J. B. Lyon, 1904, pp. 63-116. Also known as Slocum and His Men: The Twelfth Corps.

Biography of General Henry Warner Slocum, 1913

Part 1

Part 2

Source: Slocum, Charles E. The Life and Services of Major-General Henry Warner Slocum. Toledo: Slocum Publishing, 1913.

This is a complete copy of the Charles Slocum book, with additional illustrations and supplementary material and appendices.