In February, Brigadier General U. S. Grant, aided by Commodore A. H. Foote's naval gunboats, took Fort Henry on the Tennessee River and Fort Donelson on the Cumberland. This forced the Confederates out of Kentucky and a large part of Tennessee. The Confederates evacuated Nashville on February 23; it was the first Confederate state capital to fall to the Union. They then retreated to Corinth, Mississippi, where they organized a counteroffensive. The Battle of Shiloh (or Pittsburg Landing) began on April 6, when the Confederates attacked Grant's troops. They had initial success, but were driven off with heavy losses the next day. Confederate General Albert Sidney Johnston was mortally wounded on the first day of the battle. General Beauregard was his successor.Bloody battles raged throughout the west.
General H. W. Halleck, who had been given command of all the western Union armies, had ordered Major General John Pope to take New Madrid and Island No. 10 on the Mississippi River. With the cooperation of Foote's naval forces, this was done on April 7. Halleck then marched the combined forces of Major Generals Grant and Don C. Buell against Corinth, Mississippi, where the Confederates had retired after Shiloh. Halleck arrived on May 30 to find the Confederates gone. In April Captain D. G. Farragut with a naval force took New Orleans, leaving the Confederates in control of the river only between Vicksburg and Port Hudson.
A Confederate invasion of Kentucky under General Braxton Bragg was turned back by General Buell's forces at the Battle of Perryville. However, Buell did not forcefully pursue Bragg, and was replaced by William S. Rosecrans. The armies of Bragg and Rosecrans met at the Battle of Stones River (or Murfreesboro) and fought to a standstill December 31, 1862 January 2, 1863. The battle is considered a Union victory, however, because Bragg retreated south on January 3.
Early in 1862, President Lincoln ordered McClellan to make a determined effort to take Richmond. McClellan planned to take the city from the east, by marching up the peninsula between the York and James rivers.
The Union army of 100,000 men was moved by water to Fort Monroe, Virginia, in late March. McClellan faced only a small Confederate force of about 17,000 men. However, he overestimated the strength of the enemy, and instead of attacking, he began a siege of the Confederate position at Yorktown, on April 5. The Confederates evacuated Yorktown after a month, during which time they were able to move reinforcements to the peninsula.
There was fighting at Williamsburg on May 5. Union troops reached and crossed the Chickahominy River on May 20. Here they were faced by a Confederate force of about 60,000, under General Joseph E. Johnston.
Meanwhile, Confederate General T. J. (Stonewall) Jackson tied down three small Union armies in the Shenandoah Valley. Making superb use of his small force, Jackson moved his men up and down the valley, fighting a series of engagements with Union troops. His rapid and deceptive maneuvering caused fear that Washington might be attacked, and consequently, the Union armies in the valley were withheld from the Peninsular Campaign.
On May 31 and June 1, General Johnston tried unsuccessfully to break through McClellan's lines outside Richmond in the Battle of Fair Oaks (or Seven Pines). Johnston was wounded in the battle, and was succeeded by General Robert E. Lee.
During the next three weeks there was little fighting. The Confederate J. E. B. Stuart, however, made a spectacular cavalry raid, circling entirely around the Union army on June 11, 12, and 13.
McClellan received reinforcements and planned to resume the offensive. Lee, however, was too quick for him and attacked the Union right flank at Mechanicsville. This was the beginning of the Seven Days' Battles. After the Battle of Gaines's Mill, McClellan moved his base of operations to Harrison's Landing, on the James River. The Confederates remained on the offensive, attacking repeatedly until by July 1 McClellan had retreated to a strong position at Malvern Hill, northwest of Harrison's Landing.
Lee's troops attacked on July 1. The assaults were all frontal and were delivered piecemeal by only part of the army. Union artillery halted them and shattered the attacking units, inflicting more than 5,300 casualties. This was the last battle of the Peninsular Campaign. The Union forces fell back and dug in at Harrison's Landing. The exhausted Confederates were ordered back to the Richmond lines for rest and reorganization.
On July 11, Halleck was appointed general-in-chief. McClellan was ordered to abandon the peninsula and withdrew by water to Aquia Creek, on the Potomac. Pope was called from the west to command the newly formed Army of Virginia. McClellan's Army of the Potomac and Pope's Army of Virginia were to join between Richmond and Washington.
Before this could happen, Lee and Jackson moved against Pope's army and maneuvered him back to the old Bull Run battleground. Here on August 2830 was fought the second Battle of Bull Run (or Second Manassas). Pope fought hard but was outgeneraled and defeated, afterwards withdrawing his troops to the defenses of Washington. Pope's army was then merged with the Army of the Potomac, with McClellan in command.
Lee invaded Maryland in early September. McClellan moved to counter the invasion, and halted the Confederates at the battles of South Mountain, September 14, and Antietam (or Sharpsburg), September 17. McClellan, however, did not vigorously pursue the exhausted Confederate army, allowing Lee to escape across the Potomac.
Angered by McClellan's inaction, Lincoln replaced him in November with General Ambrose E. Burnside. Burnside advanced to Fredericksburg, where Lee established a secure position on Marye's Heights, a bluff overlooking the town. Burnside ordered a direct assault on Lee's position, and his forces were repulsed in one of the bloodiest battles of the war.