Siege of Yorktown (1862) — Peninsula Campaign engagement

Forces and defensive preparations

The opposing sides comprised a large Union army and a smaller Confederate field force. The Confederate defenders, initially under Brig. Gen. John B. Magruder, used active troop movements and engineering works along the Warwick Line to exaggerate their strength and slow the Union. Reinforcements under Gen. Joseph E. Johnston later strengthened the position. The Union advance included elements of IV Corps led by Brig. Gen. Erasmus D. Keyes, which first engaged the Confederate line at Lee's Mill.

Siege operations and key actions

Early contact on April 5 produced local fighting and an extended exchange of artillery fire described in contemporary reports as an artillery duel. Confederate deception — conspicuous troop movements and contrived demonstrations — convinced McClellan that an assault would encounter a strongly held entrenchment, a judgment reinforced by Union reconnaissance findings. During April the Union probed the line at points such as Dam No. 1; those probes yielded limited gains but were not aggressively exploited, forfeiting an opportunity to break the Confederate position quickly.

• April 5: initial contact at Lee's Mill and beginning of siege work.
• April 16: Union probe at Dam No. 1 that failed to develop into a decisive breakthrough.
• Late April: McClellan brought heavy siege artillery forward and planned a major bombardment for early May.

McClellan also sought naval cooperation to bypass Confederate batteries at Yorktown and Gloucester Point and ascend the York River toward West Point, but the naval passage did not produce the intended envelopment. On the night of May 3, before the planned dawn attack, Confederate forces slipped away toward Williamsburg, abandoning their earthworks and avoiding a potentially costly close assault.

Aftermath and significance

Although the Confederates relinquished the immediate position, the month-long delay was strategically significant. McClellan's caution and the time consumed in preparing siege works allowed Confederate commanders to regroup and reinforce, affecting subsequent operations aimed at defending Richmond. The Yorktown action is often cited as an example of Civil War-era siegecraft, tactical deception, and how prudent withdrawal can preserve forces for later engagements.

Notable facts and context

The 1862 siege occurred near the site of the 1781 Siege of Yorktown, the climactic action of the American Revolutionary War, giving the area historical resonance. The engagement highlights several recurrent themes of the conflict: the interplay of field maneuver and entrenchment, the influence of reconnaissance on commanders' decisions, and the operational limits of combined land-and-naval efforts. Readers seeking detailed orders of battle, maps, or primary documents can consult specialized studies and archival collections for deeper research.

References in this summary point to broader topics and roles: the nature of the major general and brigadier general ranks in Civil War armies, the identities of Union and Confederate forces, and actions taken by the Union and Confederate commands during the campaign. For sequential accounts and battlefield descriptions, see resources that treat the Peninsula Campaign as a whole and the specific operations around Yorktown.