Overview
Following the Confederate victory at the Second Battle of Bull Run, General Robert E. Lee and President Jefferson Davis decided to carry the war onto Northern soil. On September 4, 1862, Lee’s Army of Northern Virginia crossed the Potomac River into Maryland. Lee hoped to obtain supplies, give Virginia farmers time to harvest their crops, weaken Northern support for the war, encourage Maryland to join the Confederacy, and possibly gain European support.
Lee advanced to Frederick and prepared Special Order Number 191. He divided his army and ordered forces under Thomas “Stonewall” Jackson, Lafayette McLaws, and Richard Anderson to capture Union positions at Martinsburg and Harpers Ferry. James Longstreet moved toward Hagerstown, while D.H. Hill protected the army’s rear.
President Abraham Lincoln placed General George B. McClellan in command of the forces defending Washington. McClellan reorganized the Union armies and advanced into Maryland. On September 13, Union soldiers from the 27th Indiana discovered a copy of Lee’s orders. McClellan now knew that Lee had divided his army and moved west to prevent the Confederate forces from reuniting.
Union and Confederate forces fought at South Mountain on September 14. The Union victory forced Lee’s defenders to withdraw, but McClellan failed to take full advantage of Lee’s vulnerable position. Meanwhile, Confederate forces captured the Union garrison at Harpers Ferry on September 15, convincing Lee to remain in Maryland.
On September 17, the armies fought the Battle of Antietam near Sharpsburg. The battle ended as a tactical draw, but the Union achieved a strategic victory because Lee’s invasion ended. Lee withdrew across the Potomac River, and Confederate forces defeated Union troops at Shepherdstown during McClellan’s limited pursuit.
The campaign ended with Lee back in Virginia. On September 22, Lincoln issued the Preliminary Emancipation Proclamation. Lincoln later removed McClellan from command of the Army of the Potomac on November 5, 1862.
Essential Facts
- Also Known As: Antietam Campaign and Robert E. Lee’s First Invasion of the North.
- Date: September 4–20, 1862.
- Location: Maryland and present-day West Virginia.
- Participants: The United States of America (USA) and the Confederate States of America (CSA).
- USA Commanders: George B. McClellan.
- CSA Commanders: Robert E. Lee.
- Who Won: The United States of America won a strategic victory.
- Era: Civil War, July–September, 1862.
Statistics
United States of America
- Casualties: 27,940, including 2,673 killed, 11,756 wounded, and 13,511 captured or missing.
- Forces Engaged: Army of the Potomac.
- Troop Strength: Roughly 102,234.
Confederate States of America
- Casualties: 10,000–20,000 killed, wounded, captured, or missing.
- Forces Engaged: Army of Northern Virginia.
- Troop Strength: Roughly 55,000.
Significance
The Maryland Campaign is important to American History because it ended Robert E. Lee’s first invasion of the North and produced a strategic Union victory. The Battle of Antietam stopped Lee’s advance even though the outcome of the battle was a tactical draw. Lee then withdrew across the Potomac River after suffering heavy losses. The campaign also had major political consequences. On September 22, 1862, President Abraham Lincoln issued the Preliminary Emancipation Proclamation, adding the destruction of slavery in the Confederacy to the Union’s war goals. Lincoln later removed George B. McClellan from command after becoming frustrated with his failure to aggressively pursue Lee’s army.
History — Robert E. Lee’s First Invasion of the North
Following the victory at the Second Battle of Bull Run (August 28 to 30, 1862), Confederate General Robert E. Lee and President Jefferson Davis decided to take the war to Northern soil in the late summer of 1862.
We cannot afford to be idle, and though weaker than our opponents in men and military equipments, must endeavor to harass if we cannot destroy them. I am aware that the movement is attended with much risk, yet I do not consider success impossible.
Robert E. Lee
On September 4, the Army of Northern Virginia started crossing the Potomac River, near Poolesville, Maryland. Robert E. Lee’s First Invasion of the North was underway, setting the stage for the Battle of Antietam.
Lee’s Goals for the Maryland Campaign
Beyond Lee’s military goals, there were both economic and political motives that prompted his First Invasion of the North
- First, the Southern armies needed provisions and supplies. Taking the war north would allow Virginia farmers to harvest their crops, unmolested by Union troops. The invasion would also enable Southern troops to seize supplies from Northern farmers.
- Lee hoped giving Northerners a taste of war would diminish their resolve. If that happened, it might bolster the prospects of Peace Democrats in the upcoming 1862 Congressional elections.
- It was possible that Maryland, one of the Border States, would join the Confederacy. As a Border State, Maryland was a Slave State that remained in the Union. However, the people of Maryland were divided, including John Wilkes Booth. Booth was an actor and staunch advocate of the Southern Cause.
- A victory on Northern soil might induce European powers to lend support to the South.
Lee’s Plan
Lee entered Maryland and proceeded to Frederick. When he arrived, he rested his men and met with his generals to devise a plan for his campaign. By September 9, Lee drafted Special Order Number 191, which outlined his course of action. Assuming that the Federal forces near Washington were still in disarray following the Second Battle of Bull Run, Lee believed that it was safe to divide his army temporarily. Lee ordered:
- Three columns — commanded by Lafayette McLaws, Richard Anderson, and Thomas “Stonewall” Jackson — were to march west and capture Union garrisons at Martinsburg and Harpers Ferry, Virginia (now West Virginia). There were two Union garrisons threatening his supply lines in the Shenandoah Valley, and Lee determined he had to eliminate them to avoid the possibility of his army being isolated in Maryland.
- Lieutenant General James Longstreet to take his column, follow Jackson, and march to the vicinity of Hagerstown, Maryland. Longstreet would guard against any potential Union resistance coming south from Pennsylvania.
- Major General D.H. Hill to take his men and follow the invasion force up the Hagerstown Road, as far as Boonsboro. Hill was to serve as a rearguard for the army’s stores and artillery.
Lincoln Turns to McClellan
Meanwhile, sensing the vulnerability of the nation’s capital, President Abraham Lincoln reluctantly turned to Major General George B. McClellan to reinvigorate the Federal forces to stop Lee’s advance. On September 2, 1862, Lincoln placed McClellan in command of “the fortifications of Washington, and all the troops for the defense of the capital.” Known for his organizational skills, McClellan merged the Army of Virginia with his Army of the Potomac and quickly transformed the demoralized Union armies into a formidable force.
Lee’s Lost Orders
Lee’s plan got underway on September 10, 1862, when Brigadier General John G. Walker’s Division headed west out of Frederick toward Harpers Ferry. Around noon on September 12, the last of the Confederate troops left Frederick. Four hours later, McClellan’s advance forces marched into Frederick and occupied the same campgrounds that the Confederates had evacuated. The next day, members of the 27th Indiana found a copy of Lee’s plans. They quickly passed the document up the chain of command, where Union officials verified its authenticity. Upon receiving the lost copy of Lee’s orders, McClellan crowed:
Here is a paper with which, if I cannot whip Bobby Lee, I will be willing to go home.
George B. McClellan
Knowing Lee had divided his army, McClellan took the initiative and advanced to a position that would prevent the Confederate army from reuniting.
It is unknown when Lee realized that McClellan knew his plans. However, what is known is that by September 14, Lee was concerned the seizure of Harpers Ferry was taking longer than expected. Lee sent a dispatch urging Jackson and McLaws to finish their task quickly and to rejoin him. When Lee learned McClellan was marching west from Frederick, he ordered Hill to hold the passes at South Mountain, which separated Lee’s soldiers from the Union army.
Battle of South Mountain
On September 14, advance elements of McClellan’s army approached three strategic passes through South Mountain—Crampton’s, Turner’s, and Fox’s Gaps—and fighting erupted. More Union troops moved forward throughout the day and gradually forced Lee to withdraw the stubborn Confederate defenders on September 15. The Union victory at the Battle of South Mountain provided McClellan with an opportunity to crush Lee’s army before it could reunite. Characteristically, McClellan did not take advantage of the Confederates’ precarious situation. While Lee hastened to reassemble his army near Sharpsburg, Maryland, McClellan spent most of the next two days devising plans and deploying troops as they poured through the South Mountain passes.
Battle of Harpers Ferry
Without the troops delayed at Harpers Ferry, Lee knew that he had little chance of winning an engagement against McClellan’s mounting superior numbers. The Confederate general was considering ending the campaign and returning to Virginia when he received word that the Union garrison at Harpers Ferry had surrendered on September 15. The Confederate victory at the Battle of Harpers Ferry convinced Lee to stand and fight. On September 16, both armies prepared for battle the next day.
Battle of Antietam — The Bloodiest Day of the Civil War
The climactic engagement of the campaign occurred on the morning of September 17, 1862, when the Army of the Potomac and the Army of Northern Virginia met along Antietam Creek, near Sharpsburg. The pitched battle went back and forth the entire day. When the Federals were on the verge of victory, General A. P. Hill and his division arrived on the scene at approximately 4:00 p.m. after a forced march from Harpers Ferry. Hill’s arrival turned the tide and prevented a Confederate defeat. The Battle of Antietam ended as a tactical draw. However, the Union won a strategic victory because Lee’s northern advance ended. The engagement was the bloodiest single-day battle during the American Civil War. McClellan’s army of approximately 75,000 men suffered 12,401 casualties, including 2,108 killed. Lee’s smaller army of approximately 55,000 soldiers suffered 10,316 casualties, including 1,546 killed.
Battle of Shepherdstown
Following a day of truce during which both sides recovered and exchanged their wounded and recovered their dead, Lee began withdrawing his army across the Potomac River at Boteler’s Ford near Shepherdstown, Virginia (present-day West Virginia). Once again, McClellan failed to press the issue.
After crossing the Potomac River, Lee left behind a rearguard of two infantry brigades and forty-five cannons, commanded by Brigadier-General William N. Pendleton, to hold the ford. It was not until late afternoon on September 19 that a detachment of Federal troops from Major General Fitz John Porter’s 5th Corps crossed the river, attacked the Confederate rearguard, and then withdrew. The next morning, Porter sent two divisions back across the river to establish a bridgehead for McClellan’s army.
By that time, Major General A. P. Hill’s “Light Division” had reversed course and marched back towards Shepherdstown in time to counterattack the advancing Union forces. When Porter received word that the Confederate force outnumbered his infantry on the Virginia side of the Potomac River, he ordered a withdrawal. The Confederate victory at the Battle of Shepherdstown persuaded McClellan to call off any further pursuit of Lee’s battered army, much to the consternation of President Lincoln and other federal officials. McClellan would later pay for his inertia when Lincoln dismissed him as commander of the Army of the Potomac on November 5, 1862.
Outcome
The Battle of Shepherdstown and Lee’s withdrawal from Maryland ended the Maryland Campaign. Although the fighting was over, the campaign precipitated a monumental aftereffect that altered the course of the war. With Lee’s army driven back across the Mason-Dixon Line, President Lincoln, on September 22, 1862, used his constitutional power as commander-in-chief to issue his Preliminary Emancipation Proclamation. The president’s “covenant with God,” which added freeing Southern slaves to the mission of the war, produced major political repercussions, especially in the North, and undoubtedly steeled the resolve to fight on in the South.
Timeline
- 1862, September 2 — President Abraham Lincoln placed George B. McClellan in command of Washington’s defenses and the troops protecting the capital.
- 1862, September 4 — Robert E. Lee’s Army of Northern Virginia crossed the Potomac River into Maryland.
- 1862, September 9 — Lee prepared Special Order Number 191 and outlined his plan to divide his army.
- 1862, September 10 — John G. Walker’s division marched west from Frederick toward Harpers Ferry.
- 1862, September 12 — The last Confederate troops left Frederick, Maryland, and McClellan’s advance forces occupied the city later that day.
- 1862, September 13 — Soldiers from the 27th Indiana discovered a copy of Lee’s Special Order Number 191.
- 1862, September 14 — Union and Confederate forces fought for Crampton’s, Turner’s, and Fox’s gaps during the Battle of South Mountain.
- 1862, September 15 — Confederate forces withdrew from South Mountain, and the Union garrison at Harpers Ferry surrendered.
- 1862, September 16 — The Army of the Potomac and Army of Northern Virginia prepared for battle near Sharpsburg.
- 1862, September 17 — The armies fought the Battle of Antietam, which ended Lee’s invasion of the North.
- 1862, September 19 — Union troops crossed the Potomac River and attacked the Confederate rearguard near Shepherdstown.
- 1862, September 22 — President Lincoln issued the Preliminary Emancipation Proclamation.
- 1862, November 5 — Lincoln removed McClellan as commander of the Army of the Potomac.
AP US History
Definition
Maryland Campaign (1862) — The Maryland Campaign was General Robert E. Lee’s first invasion of the North during the Civil War. After entering Maryland, Lee divided his Army of Northern Virginia, but Union forces discovered his orders. The Union victory at South Mountain threatened Lee’s divided army, while the Confederate victory at Harpers Ferry allowed Lee to concentrate near Sharpsburg. The Battle of Antietam ended Lee’s invasion, and the Battle of Shepherdstown ended Union pursuit. Lincoln later issued the Preliminary Emancipation Proclamation.
Alignment
The Maryland Campaign is part of the following AP US History sections:
Bibliography and Suggested Reading
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The Maryland Campaign of 1862 by General Ezra A. Carman
Ezra A. Carman was an officer in the Union Army during the Civil War. He commanded a New Jersey infantry regiment and a brigade. Carman fought in the Maryland Campaign as the Colonel of the 13th New Jersey Infantry. After the fighting of September 17, 1862, he wrote in his diary that he was preparing “a good map of the Antietam battle and a full account of the action.” In 1894, Carman was appointed as the “Historical Expert” to the Antietam Battlefield Board. Carman and the others gathered accounts from hundreds of veterans, researched thousands of letters and maps, and collected the material into the hundreds of cast iron tablets that still mark the field today. Carman also wrote an 1,800-page manuscript on the Maryland Campaign, from its start in northern Virginia through McClellan’s removal from command in November 1862. Carman’s work is available in a 3-volume set.
