As Union commander George McClellan moved the Army of the Potomac up the Peninsula in early 1862, the Union army still had a nearly 2-1 advantage in manpower, so Army of Northern Virginia commander Joseph E. Johnston continued to gradually pull his troops back to a line of defense nearer Richmond as McClellan advanced. In conjunction, the Union Navy began moving its operations further up the James River, until it could get within seven miles of the Confederate capital before being opposed by a Southern fort.

McClellan continued to attempt to turn Johnston’s flank, until the two armies were facing each other along the Chickahominy River. At this point, the Union army was close enough to Richmond that they could see the city’s church steeples, but they would come no closer. By the end of May, Stonewall Jackson had startlingly defeated three separate Northern armies in the Shenandoah Valley, inducing Lincoln to hold back the I Corps from McClellan. When McClellan was forced to extend his line north to link up with troops that he expected to be sent overland to him, Johnston learned that McClellan was moving along the Chickahominy River.

It was at this point that Johnston got uncharacteristically aggressive. Johnston had run out of breathing space for his army, and he believed McClellan was seeking to link up with McDowell’s forces. Moreover, about a third of McClellan’s army was south of the river, while the other parts of the army were still north of it, offering Johnston an enticing target. After a quick deluge turned the river into a rushing torrent that would make it impossible or the Union army to link back up or aid each other, Johnston drew up a very complex plan of attack for different wings of his army, and struck at the Army of the Potomac at the Battle of Seven Pines on May 31, 1862.

By the time the fighting was finished, nearly 40,000 had been engaged on both sides, and it was the biggest battle in the Eastern theater to date (second only to Shiloh at the time). Although it was inconclusive, McClellan was rattled by the attack, and near the end of the fighting that night Johnston had attempted to rally his men by riding up and down the lines only to be nearly blown off his horse by artillery fire and having to be taken off the field. Johnston explained, “About seven o'clock I received a slight wound in the right shoulder from a musket-shot, and, a few moments after, was unhorsed by a heavy fragment of shell which struck my breast. Those around had me borne from the field in an ambulance; not, however, before the President, who was with General Lee, not far in the rear, had heard of the accident, and visited me, manifesting great concern, as he continued to do until I was out of danger.”

In addition to having a direct impact on the rest of the fighting in 1862, the Peninsula Campaign would remain in the minds of Union soldiers and leaders over the next few years. Lincoln’s frustrations with different generals in the Army of the Potomac led to his promotion of Ulysses S. Grant as chief of all armies ahead of the Overland Campaign of 1864. When the Army of the Potomac was thwarted at the Battle of the Wilderness in early May 1864, it found itself in a similar position as Hooker at Chancellorsville, McClellan on the Peninsula, and Burnside after Fredericksburg. Union soldiers got the familiar dreadful feeling that they would retreat back toward Washington, as they had too many times before. This time, however, Grant made the fateful decision to keep moving south, inspiring his men by telling them that he was prepared to “fight it out on this line if it takes all Summer”.