What was the main purpose of General Sherman's March to the Sea?
To divide the south.
Gen. Sherman knew he had the troops to defeat any confederates who stood in his way. He took a very literal scorched earth campaign in his desire to literally divide the south. Earlier in 1864 he had defeated Gen. Hood's army north and west of Atlanta and then proceeded to Atlanta which he torched. He then divided his forces into four groups who marched via separate routes from Atlanta to Savannah, burning fields, houses and destroying everything in his path.
Sherman's mission was to send a signal to the south that they were defeated.