The reasons Sherman marched to the sea are:
1.-- To disrupt comunication, and roads.
The confederate forces needed to stay in contact, sometimes their armies were spread out on a long perimeter. Also they needed the railroads to get supplies and troops around.
2. --To Stop Confederate reinforcements General Grant was fighting east in Virginia, where the main confederate army was. Sherman stopped General Johnston's troops from reinforcing Lee. This let Grant besige Richmond.
3.--To lower the South's Morale
Public support is important in a war
4.-- To destroy the South's economy and supplies.
The South's resources were already not as good as th North's, and this made it even worse.
What he did
Sherman's job was to keep General Joseph E. Johnston busy so that he can't reinforce Lee. He also had to take Atlanta. At first progress was slow, but he wasn't in much of a hurry. After Atlanta Sherman decided to march to the sea, and bring the war to a speedy end by using up or destroying the South's resources.
At first Sherman only inched toward Atlanta, confederate general Johnston held good intrenchments, and Sherman could not flank him to cut off his comunication line with Atlanta. No major Battles ocurred. But soon Sherman was very close to Atlanta. Jefferson Davis didn't like Johnston's defensive strategy, and replaced him with Hood, because he is more agressive. Hood did attack, and it was a disastrous defeat. After a four month campaign Atlanta falls to the Union, the citizens are evacuated, and Atlanta burnt.
Savannah Campaign:Sherman now had an Army of 60,000, and only the best stayed with Sherman, the weak were sent north. Most of his men have been with him for a long time, they called Sherman Uncle Billy. These 60,000 soldiers, and 8,000 horses and mules had to be fed, however. Sherman instructed them to forage around for food, they went through Georgia like a swarm of locusts. And if they didn't need it they destrotyed it, 13,000 cattle fell into their hands, and they burned industrial buildings, like sawmills, foundries, etc. His lines were spread out, so that their path of destruction was 50 miles wide. His goal in this campaign was to make it to Savannah, and the sea.
"Make Georgia Howl"
Sherman's strategy of total war was controversial, but it had the full support of President Lincoln, and General Grant. Sherman argued that , although it was brutal, it would bring the war to a speedy end. He warned his troops not to harm civilians, or destruct property (if not ordered to), but this wasn't inforced much. The general is still hated by many Southerners today.
After losing Atlanta Confederate General John Bell Hood retreated to Alabama and later tried to cut off Sherman's supply lines, and tried to draw him away from Georgia by Attacking Nashville Tenessee. In response to this Sherman sent a portion of his army after Hood, Hood lost some battles after which he was no longer a threat. There were not many other significant engagements during the Savanna campaign, the confederates could never bring together more than 20,000 soldiers to oppose Sherman, since most of them were fighting up north. little skirmishes ocurred here and there.
If Sherman just ripped out the rails of the railroad then they could be put back in just as easily. For this reason he ordered his men to put the rails on a wood fire, and then bend them so that they can't be used anymore. These came to be known as 'Sherman Neckties'.
Arrival in Savahnna
Sherman's arrival in Savannah marked the end of his march to the sea.When Sherman arrived at Savanna it was fortified by 10,000 men, for ten days they held out while Sherman prepared for an attack, but the commander realized that resistance is futile and fled. On December 22, 1864 Sherman sends Lincoln a telegraph saying " His excellency Presient Lincoln. I beg to present you as a Christmas gift the city of Savannah. With 150 heavy guns and plenty of amunition, and about 25,000 bales of cotton." Sherman also had to capture Ft. McCallister, it took 2,000 union soldiers to take it in about 15 minutes.
Sherman became a celebrity after completing his march. He became a household name.