The Siege of Yorktown was an almost month long affair that resulted in the Union using the town as a port and supply depot in their further efforts to advance towards Richmond, the capital of the Confederacy. Though the siege proved inconclusive in terms of actual victory, it can be contested that the Union gained an advantage that would aid in their eventual overall victory in the Civil War. An estimated 482 men lost their lives in this battle of the Peninsular Campaign: 182 from the McClellan-led Federal forces and 300 from the Rebels under Joseph E. Johnston's command. The siege came to a close when the Confederate forces abandoned the area and retreat towards Williamsburg due to their forces being significantly outnumbered to the Union.
President Abraham Lincoln was considering the notion of launching an attack on Richmond from the outskirts of Washington, D.C. when Major General George B. McClellan suggested using the peninsula formed by the York and James Rivers. Unbeknownst to both men, the Confederacy was anticipating such a strategy and began fortifying and strengthening the lines along the peninsula under the command of Major General John B. Magruder. While General Robert E. Lee, military advisor to Confederate President Jefferson Davis, was thinking of reinforcing the 11,000 men Magruder had, General Joseph E. Johnston suggested the line be abandoned in favor of concentrating Magruder's forces into a better defense of Richmond. The Army of the Peninsula was then added to the Army of Northern Virginia with Johnston in command while Magruder was given control of a portion of Johnston's men.When McClellan heard that there was a smaller force fortifying the area around Yorktown, he turned away from Richmond in favor of taking on the Rebels in that region. Unfortunately for the Confederates, Johnston and most of his army was not on the peninsula when McClellan reached them, leaving Magruder and two small divisions to fight against the Yankees. Fortunately, for Magruder, he used theatrics to persuade McClellan and his troops there was a much larger army occupying Yorktown. McClellan then insisted on building siege fortifications to hopefully take on this supposedly large group of forces.While the Union batteries were continuously firing upon Yorktown, there was only one that actually fired upon Confederate forces. Johnston, however, always knew that he would have the troops leave Yorktown, and began this procedure on the night of May 3 by ceasing all diverting fire from his heavy guns. The following morning, McClellan and the Union soldiers discovered that Yorktown was deserted by the Confederates, leaving behind weaponry that would aid them in future battles, such as the newly discovered land mines. Seizing these weapons would prove to be a great benefit to the Union as they would go on to ultimately win the Civil War three years later. At the time of the conflict, there had never been such a humongous amount of artillery used in the world. McClellan eventually left the Yorktown Peninsula in August 1862 leaving behind some units to keep control of Yorktown through the end of the war when Major General Ulysses S. Grant requested that Yorktown be abandoned at the beginning of the siege of Petersburg.