In March, Grant was promoted to lieutenant general and placed in command of all Union armies. He stationed himself with the Army of the Potomac, still under the nominal command of Meade. In May he crossed the Rapidan River in Virginia and was stopped by Lee in the bloody, indecisive two-day Battle of the Wilderness (May 56).
Grant expressed his determination not to withdraw by saying he would fight it out on this line if it takes all summer. He tried a flanking movement and again was halted by Lee in a series of battles near Spotsylvania Court House, May 819. Some of the most savage fighting of the war took place there at a Confederate salient called the Bloody Angle. Grant tried another flanking movement, but Lee anticipated it, and moved to a new position near Cold Harbor. On June 3, Grant launched a large-scale frontal attack on the Confederate position, but was beaten back with heavy losses.
Grant's next move, crossing the James River in a wide flanking march that shifted his base of supply, nearly caught Lee off guard. Only Beauregard's prompt action in assembling reserve troops saved Petersburg, Virginia, the key to Richmond. Grant then began a siege of Petersburg. Both sides dug long lines of trenches. All attempts by the Union forces to break through the Confederate defenses failed. Union engineers tunneled under a strong point in the Confederate lines and placed 8,000 pounds (3,600 kg) of gunpowder there. On July 30 the powder was detonated, and Union troops attacked the stunned Confederates. The attacking troops, however, became trapped in the crater made by the explosion, and suffered heavy losses.
In the hope of forcing Grant to withdraw troops from the lines, General Jubal A. Early attempted a diversion from the Shenandoah Valley. Early crossed the Potomac into Maryland and threatened Washington. Lincoln was under fire while inspecting a fort at the outskirts of the capital. Early, however, did not have enough troops to press home the attack and withdrew to the Shenandoah Valley. Grant then organized an army under General P. H. Sheridan to destroy Early's army and lay waste to the Shenandoah Valley, the Breadbasket of the Confederacy. Sheridan decisively defeated Early at Cedar Creek on October 19.
Sherman started an advance against Atlanta in May, at the same time that Grant began the campaign in the East. Sherman's force was so much larger than his enemy's that he could use two of his armies to hold Johnston, while using the third to threaten the Confederate flank or rear. However, Johnston was a master of delaying tactics, and refused to be trapped into a general battle.
As Johnston slowly fell back toward Atlanta, Sherman became impatient and ordered a frontal attack at Kennesaw Mountain, Georgia (June 27). It failed, but he continued his flanking movements and crossed the Chattahoochee River, threatening Atlanta. President Davis then replaced Johnston with General John B. Hood. Hood attacked, but gained no advantage in the battles of Peachtree Creek and Atlanta (July 20 and 22). The city was then besieged. Hood gave up Atlanta in September and attempted to attack Sherman's lines of supply, but was unsuccessful.
Sherman sent Thomas in pursuit of Hood, then began one of the most remarkable military exploits of the war. Abandoning its supply lines and living off the land, Sherman's huge army marched across central Georgia to Savannah, destroying supply depots, railroads, barns, and crops as they went. They left a swath of destruction some 60 miles (96 km) wide and 300 miles (480 km) long, demonstrating that the Confederates could no longer defend their own territory.
As Hood moved northward, he attacked General John M. Schofield at Franklin, Tennessee, on November 30. The battle was short, sharp, and furious. Schofield beat off Hood. Six Confederate generals were killed. At Nashville on December 15 and 16 Thomas attacked, destroying Hood's army as an effective force.