Overview
After the Union defeat at the First Battle of Bull Run (July 21, 1861), George B. McClellan took command of the Union war effort in the East. He reorganized the Army of the Potomac and developed a plan to capture Richmond, Virginia, by moving through the Virginia Peninsula. His offensive started on March 17, 1862, when the Union transported roughly 120,000 soldiers to Fort Monroe.
Confederate forces had constructed the Warwick Line across the peninsula under John B. Magruder. When Union forces advanced toward Yorktown, Virginia, in early April, Magruder had only about 12,000 men defending approximately 12 miles of fortifications. However, he repeatedly moved troops behind his defenses to make his army appear larger. McClellan believed more than 40,000 Confederates defended the line and ordered his army to prepare for a siege.
While Union troops constructed siege works, Confederate leaders transferred reinforcements to the peninsula. By late April, Joseph E. Johnston commanded roughly 56,000 troops, who stood between McClellan and Richmond. McClellan made one significant attempt to break the Confederate defenses on April 16, when William F. “Baldy” Smith attacked near Dam No. 1. Union soldiers initially pushed Confederate forces back, but a counterattack forced them to withdraw.
McClellan then assembled heavy artillery, eventually positioning 101 siege guns against the Confederate defenses. Johnston concluded that his army could not withstand the expected bombardment and recommended a withdrawal. Confederate leaders eventually approved his plan.
On the night of May 3, Johnston ordered artillery fire to cover the withdrawal of his troops and supply trains toward Richmond. The next morning, Samuel P. Heintzelman observed the abandoned Confederate positions from an observation balloon. The Union gained a tactical victory, but the delay at Yorktown gave Confederate leaders valuable time to strengthen Richmond’s defenses and concentrate forces against McClellan’s campaign.
Essential Facts
- Also Known As: Battle of Yorktown.
- Date: April 5–May 4, 1862.
- Location: York County and Newport News, Virginia.
- Participants: The United States of America (USA) and the Confederate States of America (CSA).
- USA Commanders: George B. McClellan.
- CSA Commanders: John B. Magruder, Joseph E. Johnston.
- Who Won: The United States won the Siege of Yorktown.
- Campaign: Peninsula Campaign.
- Era: Civil War, January–June, 1862.
Statistics
United States of America
- Casualties: 182 killed, wounded, captured, or missing.
- Forces Engaged: Army of the Potomac.
- Troop Strength: Roughly 121,500.
Confederate States of America
- Casualties: 300 killed, wounded, captured, or missing.
- Forces Engaged: Army of the Peninsula, Army of Northern Virginia.
- Troop Strength: Roughly 35,000.
Significance
The Siege of Yorktown is important to American History because it delayed George B. McClellan’s advance toward Richmond, Virginia, during the Peninsula Campaign. Although McClellan commanded a much larger army, John B. Magruder used deception to convince him that Confederate defenses along the Warwick Line were stronger than they actually were. McClellan chose to conduct a siege instead of launching a major attack. The month-long delay allowed Confederate leaders to reinforce their army and strengthen defenses closer to Richmond. Although Joseph E. Johnston eventually abandoned Yorktown and gave the Union a tactical victory, the delay helped the Confederates concentrate enough forces to protect their capital and ultimately derail McClellan’s campaign.
History
Within twenty-four hours of the Union’s defeat at the First Battle of Bull Run (July 21, 1861), the Lincoln administration called upon George B. McClellan to lead the Union war effort in the East. McClellan spent the first few months of his new command fortifying Washington, DC, and reorganizing federal forces. The Northern public and politicians, however, wanted action. Accordingly, McClellan devised plans for an offensive to capture the Confederate capital at Richmond, Virginia, to bring a quick conclusion to the war.
Peninsula Campaign
Although President Abraham Lincoln favored an overland assault on Richmond from the Washington area, McClellan developed a more complex strategy. Correctly believing that Confederate leaders expected a direct onslaught against the Confederate capital, McClellan proposed to outmaneuver the Confederate army guarding Richmond and to launch an offensive from the southeast, up the Virginia Peninsula.
The Virginia Peninsula is a strip of land in southeastern Virginia that runs from the northwest to the southeast. It is bordered on the north and east by the York River and on the south and west by the James River. Although nearly the entire area was behind Confederate lines early in the war, the Union maintained possession of Fort Monroe at the very tip of the peninsula.
McClellan planned to use the Union’s superior naval resources to transport the Army of the Potomac down the Chesapeake Bay, to disembark at Fort Monroe, and then to move up the peninsula, attacking Richmond from the rear. In early March, the Confederate Navy launched the ironclad CSS Virginia, posing a menace to federal control of the waters around Fort Monroe. Virginia’s launch threatened the success of McClellan’s plan. The appearance of the USS Monitor at the Battle of Hampton Roads forced Virginia’s withdrawal on March 9 and erased the Confederate threat.
McClellan Advances
McClellan’s offensive began on March 17, when he began transporting his army of approximately 120,000 men to Fort Monroe. McClellan arrived on site on April 2, and two days later, the Army of the Potomac began its advance up the peninsula toward Yorktown.
Confederate Defenses
Confederate officials had prepared for McClellan’s offensive. In 1861, Major General John Bankhead Magruder, commander of the Army of the Peninsula, began constructing defensive lines across the Virginia Peninsula. The mainline, known as the Warwick Line, connected Yorktown on the York River to the headwaters of the Warwick River and then extended southwest to the confluence of the Warwick and James Rivers.
McClellan Orders a Siege
As McClellan’s men began their advance up the peninsula on April 4, they soon encountered Confederate skirmishers who quickly fell back to the Warwick Line. Magruder had only 12,000 soldiers at his disposal to defend the line, which stretched for approximately twelve miles across the peninsula. When McClellan’s immense army could have overrun the Confederate defenses, Magruder’s creativity made up for his lack of manpower. As McClellan’s scouts watched, Magruder skillfully moved his men about, behind his defenses, creating the illusion that his force was much larger than it really was. The charade deceived McClellan into estimating the size of Magruder’s army to be over 40,000 soldiers. Magruder’s theatrics, combined with McClellan’s tentative nature, prompted the Union general to order his men to entrench and prepare for a siege, rather than to overwhelm their adversaries.
Confederate Reinforcements
As McClellan’s army dug in and constructed siege fortifications, Confederate officials began shifting soldiers from northern Virginia to the Virginia Peninsula. By late April, Confederate leaders merged the Army of the Peninsula into the Right Wing of the Army of Northern Virginia and General Joseph E. Johnston arrived to take command of the 56,000 troops that now stood between McClellan and Richmond.
Battle of Dam No. 1
During the four-week siege, McClellan made one major attempt to break the Confederate line. On April 16, Union forces, commanded by Brigadier General William F. “Baldy” Smith, crossed the Warwick River to test the Confederate defenses near Dam No. 1, where Union Brigadier General Winfield S. Hancock had reported a potential vulnerability. McClellan’s orders to avoid a general engagement hampered Smith. Union soldiers pushed the enemy back until a Confederate counterattack drove Smith’s men back across the bridge, thus ending the only real Federal attempt to breach the Confederate defenses during the siege.
Johnston Vanishes
For the next two weeks, McClellan continued to amass siege artillery in front of the Warwick Line, while trying unsuccessfully to convince the navy to outflank the Confederates by moving flotillas up the York and James Rivers. By April 22, Johnston realized that his defenders had no chance of withstanding the looming barrage from McClellan’s artillery, which eventually totaled 101 siege guns. Consequently, Johnston recommended withdrawing his forces to new defensive lines closer to Richmond. However, Confederate President Jefferson Davis, heeding the advice of his military adviser Robert E. Lee, ordered Johnston to remain in his current position. Finally, as McClellan made his final preparations to unleash the full might of his artillery, Johnston’s views prevailed. On the night of May 3, Johnston ordered a covering artillery barrage of his own, as his troops and supply trains began falling back toward Richmond. The next morning, Union Major General Samuel P. Heintzelman boarded an observation balloon, ascended over the Confederate defenses, and reported to a stunned McClellan that the Confederates had vanished during the night.
Outcome
Because McClellan’s army held the field after forcing the Confederate defenders to abandon the Warwick Line, the Siege of Yorktown was tactically a federal victory. In addition, the Union suffered only 182 casualties compared to 300 for the Confederacy.
Timeline
- 1861 — John B. Magruder constructed defensive lines across the Virginia Peninsula, including the Warwick Line.
- 1861, July 21 — Confederate forces won the First Battle of Bull Run.
- 1862, March 8–9 — Union and Confederate ironclads fought the inconclusive Battle of Hampton Roads.
- 1862, March 17 — General George B. McClellan launched the Peninsula Campaign with an amphibious landing near Fort Monroe.
- 1862, April 2 — McClellan arrived at Fort Monroe.
- 1862, April 4 — The Army of the Potomac advanced toward Yorktown and encountered Confederate skirmishers near the Warwick Line.
- 1862, April 5 — The Siege of Yorktown started.
- 1862, April 16 — Union forces attacked Confederate defenses near Dam No. 1 but withdrew after a Confederate counterattack.
- 1862, April 22 — Johnston concluded that Confederate forces could not withstand McClellan’s planned artillery bombardment and recommended withdrawing toward Richmond.
- 1862, May 3 — Johnston ordered artillery fire to cover the Confederate withdrawal toward Richmond.
- 1862, May 4 — Union forces discovered that the Confederates had abandoned the Warwick Line, ending the Siege of Yorktown.
AP US History
Definition
Siege of Yorktown (1862) — The Siege of Yorktown was fought from April 5 to May 4, 1862, during the Peninsula Campaign and resulted in a tactical Union victory. John B. Magruder used deception to convince George B. McClellan that Confederate forces along the Warwick Line were much larger than they actually were. McClellan responded by preparing for a siege instead of attacking. Union forces failed to break the Confederate line at Dam No. 1, while Confederate reinforcements arrived under Joseph E. Johnston. Before McClellan could launch a massive artillery bombardment, Johnston withdrew toward Richmond, Virginia.
Alignment
The Siege of Yorktown is part of the following AP US History sections:
