Battle of Yorktown
Marching from Fort Monroe, Maj. Gen. George B. McClellan’s army encountered Maj. Gen. John B. Magruder’s small Confederate army at Yorktown behind the Warwick River. Magruder’s theatrics convinced the Federals that his works were strongly held. McClellan suspended the march up the Peninsula toward Richmond, ordered the construction of siege fortifications, and brought his heavy siege guns to the front. In the meantime, Gen. Joseph E. Johnston brought reinforcements for Magruder. On 16 April, Union forces probed a weakness in the Confederate line at Lee’s Mill or Dam No. 1, resulting in about 309 casualties. Failure to exploit the initial success of this attack, however, held up McClellan for two additional weeks, while he tried to convince his navy to maneuver the Confederates’ big guns at Yorktown and Gloucester Point and ascend the York River to West Point thus outflanking the Warwick Line. McClellan planned for a massive bombardment to begin at dawn on May 4, but the Confederate army slipped away in the night toward Williamsburg. (NPS summary)
Siege at Yorktown
Having decided on a siege operation McClellan quickly discovered that the execution of that concept was going to be much more difficult than ordering it. The roads had been reduced by the rains to a point of being incapable of handling the massive weights of the siege artillery. McClellan was forced to seek out the assistance of his engineers before the siege operations could begin. The construction of a transportation infrastructure was tasked to BG John G. Barnard, Chief Engineer for the Army of the Potomac.
Barnard realized that "extensive preparations" would be required before any artillery could be placed. He examined Wormley's Creek and decided to make this the focal point of these preparations. To shorten the distance the guns would have to travel overland he decided to make the creek the entry point for the arriving siege guns and material. This plan required the construction of 5,000 yards of road, corduroy of all pre-existing roads, numerous crib work bridges to span ravines, the widening of the mill dam, three pontoon bridges, and many other projects. Barnard's engineer assets included Companies A, B, and C of the US Engineer Battalion, the 15th New York Engineers, and the 50th New York Engineers. These men worked nearly non-stop supported by large details from the line companies but it was not until the 17th of April before "it was deemed practicable to commence the construction of batteries."
McClellan intended an incredible display of firepower to blast the Confederates from their works. After a joint reconnassaince by Barnard and Chief of Artillery BG William F. Barry it was decided that fourteen batteries (a fifteenth battery was later added) would be constructed. These would house 75 artillery pieces, ranging in size from mammoth 200lb Parrotts to 12lb field pieces, and 29 10'-13" mortars. The work began immediately and was progressed on a vigorous schedule. The staggering pace of work did not impress everyone, however. President Lincoln frustrated by the delays wrote to McClellan that his demand for more heavy artillery "argues indefinite procrastination." BG Oliver O. Howard agreed writing that he experienced "a considerable impatience...because of the slowness of the army" and that "the reasons given for such delay seemed insufficient." McClellan shrugged off the complaints confident that he was pursuing the most effective strategy.
Eventually enough progress was made so that McClellan desiginated May 5th as the day for the grand barrage. Once the enemy guns guarding the river were destroyed the US Navy would add the weight of their guns to the bombardment. McClellan thought two days of this type of pounding would be enough to force a surrender. Magruder had no idea of subjecting his troops to such a beating. On the night of 3 May the Confederate gunners opened a barrage of their own. Under cover of the artillery fire Magruder's forces evacuated the city and the outlying defenses.
The following morning the balloon Intrepid with Thaddeus Lowe and BG Samuel Heintzelman aboard ascended to view the Confederate lines. They reported no enemy remaining in sight. The advanced Union forces entered the Confederate works without a fight. Yorktown was won. Left behind were "torpedoes", or land mines, designed by Confederate General Gabriel Rains. PVT John Pruyne, of Co F, 52nd Pennsylvania won the unfortunate distinction of being the first man killed by these devises. The practice was deemed barbaric by McClellan who vowed to have Confederate POW's conduct search and disarming operations.
The great Federal arsenal assembled to humble the Confederate defenders had fired a mere 141 rounds. Magruder's bold stand in the face of long odds had purchased a month for the Confederate high command to organize a defense of Richmond. They did not waste the opportunity. By the end of the 30 day operation the Confederate forces gathered for the fight for the capital nearly equalled those of McClellan. Having thus accomplished the defensive concentration that McClellan feared in an overland advance the value of the indirect approach was lost,