July 6, 1864 – Confederates from Lieutenant General Jubal Early’s Army of the Valley captured Hagerstown, Maryland, as Federals scrambled to stop their drive on Washington.

By this time, Early’s force had marched north “down” Virginia’s Shenandoah Valley and crossed the Potomac River into Maryland. Early planned to threaten Washington in hopes that Lieutenant General Ulysses S. Grant would divert Federal forces from laying siege to Petersburg, south of Richmond.
The Confederates received fresh supplies, including new shoes, from Richmond and resumed their eastward advance through Maryland on the 6th. A cavalry brigade under Brigadier General John McCausland entered Hagerstown and demanded $20,000 from the residents as reparations for Federal destruction in the Shenandoah Valley. Residents quickly paid the ransom. The main Confederate force advanced through the South Mountain gaps.
Meanwhile, Grant realized that Early’s Confederates were no longer in front of Petersburg as he began receiving panicked messages of a Confederate force approaching Washington. Confident that such a force could not seriously threaten the capital, Grant reluctantly detached Brigadier General James B. Ricketts’s division from VI Corps and some dismounted cavalry to bolster defenses there.
Major General Franz Sigel, commanding the Federal garrison at Harpers Ferry, informed Washington, “My troops are preparing for action.” However, Sigel still expected the Confederates to attack him and did not know that Early had bypassed him and gone into Maryland. Sigel would not leave Harpers Ferry undefended to pursue the Confederates.
This left Major General Lew Wallace, commanding the Federal Middle Department, to defend Baltimore and Washington from Early’s army. Wallace hastily gathered 2,300 troops, mostly raw recruits and militia, and moved them west from Baltimore to Monocacy Junction, just southeast of Frederick. This position enabled Wallace to defend the roads leading to both Baltimore and Washington.
On the 7th, Wallace’s force was augmented by 230 troopers of the 8th Illinois cavalry and a six-gun battery. Until Ricketts’s division could arrive, these were all the troops that Wallace could muster. The Federal troopers, led by Lieutenant Colonel David R. Clendenin, rode west and located Early’s force, which was heading for the Catoctin Pass.
The Federals brought up two guns and, according to Clendenin, proceeded “to shell the enemy skirmish line with effect.” However, the main Confederate force eventually came up, and Clendenin reported, “After five hours’ skirmishing, the enemy being heavily re-enforced and flanking me, I was compelled to fall back on Frederick.”
Clendenin’s force joined with another Federal force outside Frederick. He wrote, “Placing the guns rapidly in position, I cleared the road of cavalry and opened on the head of the approaching column, which fell back and deployed on our left bringing up artillery, which was posted south of the Hagerstown pike in a commanding position.” More Federal reinforcements arrived, which repelled a Confederate attack and pushed the enemy back to the Catoctin Pass.
By this time, panic was spreading through Washington. Wallace’s force was too small to hold off Early, Sigel could not be counted upon to help, and Major General David Hunter’s Federal army, which was supposed to have kept Early in the Valley, was way off in West Virginia. A Federal division was on its way, but it would not be enough. Chief of Staff Henry W. Halleck wired Grant:
“Until more forces arrive we have nothing to meet that number in the field, and the militia is not reliable even to hold the fortifications of Washington and Baltimore. It is the impression that one-third of Lee’s entire force is with Early and (John C.) Breckinridge, and that (Robert) Ransom has some 3,000 or 4,000 cavalry. If you propose to cut off this raid and not merely to secure our depots, we must have more forces here. Indeed, if the enemy’s strength is as great as represented, it is doubtful if the militia can hold all of our defenses. I do not think we can expect much from Hunter. He is too far off and moves too slowly. I think, therefore, that very considerable re-enforcements should be sent directly to this place.”
The next day, Grant sent the rest of VI Corps under Major General Horatio G. Wright to Maryland. He also sent XIX Corps, which had just arrived at Fort Monroe after returning from the Red River campaign. Grant then wrote Halleck, “If the President thinks it advisable that I should go to Washington in person, I can start in an hour after receiving notice, leaving everything here on the defensive.”
In Maryland, Ricketts’s division arrived at Monocacy Junction via railroad to reinforce Wallace, who pulled all the Federals out of Frederick. Wallace now had nearly 6,000 troops on the Monocacy River to face Early’s 10,000 approaching Confederates.
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References
CivilWarDailyGazette.com; Davis, Jefferson, The Rise and Fall of the Confederate Government: All Volumes (Heraklion Press, Kindle Edition 2013, 1889), Loc 20411-20; Denney, Robert E., The Civil War Years: A Day-by-Day Chronicle (New York: Gramercy Books, 1992 [1998 edition]), p. 433-34; Foote, Shelby, The Civil War: A Narrative: Volume 3: Red River to Appomattox (Vintage Civil War Library, Knopf Doubleday Publishing Group, Kindle Edition, 2011), Loc 9345-55, 9356-72, 9393-434; Fredriksen, John C., Civil War Almanac (New York: Checkmark Books, 2007), p. 465-66; Freeman, Douglas Southall, Lee (Scribner, Kindle Edition, 2008), Loc 7787; Lewis, Thomas A., The Shenandoah in Flames: The Valley Campaign of 1864 (Alexandria, VA: Time-Life Books, 1983), p. 69-73; Long, E.B. with Long, Barbara, The Civil War Day by Day (New York: Da Capo Press, Inc., 1971), p. 534-35; McPherson, James M., Battle Cry of Freedom: The Civil War Era (Oxford History of the United States Book 6, Oxford University Press, Kindle Edition, 1988), p. 756-57; Wert, Jeffry D., Historical Times Illustrated Encyclopedia of the Civil War (New York: Harper & Row, 1986, Patricia L. Faust ed.), p. 233-34, 504