On March 10, 1864, Ullysses S. Grant is named to succeed Henry Halleck as the commander of the Union armies. Lincoln tells Grant that he will not interfere with his command decisions, and that he wants him to make use of the armies. Lincoln believes that Grant will take action and be decisive, unlike his predecessors. One of the first things that Grant does is put an end to prisoner exchanges, in an effort to decrease the number of men available to the Southern armies.
In early May, Grant and George Meade move across the Rapidan River in Virginia with 100,000 men and head towards Richmond. The following day, William T. Sherman leads his 110,000 men out of Chattanooga towards Georgia and the forces of Joseph E. Johnston. Sherman's goal is Atlanta. The Overland Campaign and the Atlanta Campaign were underway. The forces of Grant and Lee clash throughout the Wilderness and at Spotsylvania,where Grant is determined to hold the line and chase Lee and wear his army down. At the same time, Sherman is blazing his way to Atlanta, with Johnston's forces continually pulling back in front of him. Johnston's maneuvers are actually skillful, and preserve his forces, but ultimately will cost him his command.
On June 3, 1863 the Battle of Cold Harbor commences and Grant throws his forces at strong Confederate positions with terrible results. 12,000 Union soldiers fall on this day alone. In less than two months, Grant has suffered more than 60,000 casualties. Lee's army has suffered half that, but the losses are more devastating because of the declining manpower of the South. Grant understands this, and realizes that he has made a grave mistake at Cold Harbor.
Two weeks later, Lee repulses a Union advance on Petersburg and Grant begins his siege of the city. The Confederates find brief success in stemming Sherman's advance at Kenesaw Mountain, Georgia and in a raid led by Jubal Early into Maryland. Soon after, Early is pushed back by General Lew Wallace and Johnston is replaced by John Bell Hood, who takes the offensive against Sherman. On July 22, Hood attacks Sherman and suffers heavy losses. Then again on July 28 with the same results.
On July 30, 1864, following a plan devised by Ambrose Burnside, the Union forces dig a mine under the Confederate lines outside of Petersburg and fill it with explosives. When the explosives are detonated, it breaks the line but also creates a gaping crater that the Union forces march straight into, rather than around. The Union forces are caught in the crater and suffer tremendous casualties -- 4,000 men are lost. Burnside is relieved of duty. The Siege of Petersburg continues.
With the Confederacy starving and running out of supplies, Admiral David Farragut takes the port at Mobile Bay, Alabama on August 23, further choking the Southern supply lines. Then, on September 1, John Bell Hood withdraws from Atlanta and Sherman marches in the next day. With Lee in Petersburg under siege and Hood on the run in Georgia, that left forces led by Jubal Early free to move about the East. Grant puts Philip Sheridan in command of a force that chases Early's and engages at Winchester Creek and Cedar Creek. The turn of events and Union victories help Abraham Lincoln win re-election on November 8, 1864 by a slim margin of less than half a million votes over George McClellan.
After the election, Sherman begins his legendary and brutal March to the Sea, heading towards Savannah, destroying everything in his path. At Nashville, John Bell Hood attacks, hoping to sever Sherman's supply line, but his forces are all but wiped out over two days. On December 22, Sherman reaches Savannah, and has successfully cut the Confederacy in two, horizontally.