March To The Sea (aka The Savannah Campaign)
William Tecumseh Sherman successfully captured Atlanta, Georgia in September 1864. However, he soon determined he could not continue to supply his large army over the vulnerable railroad linking Atlanta with Tennessee nor could he effectively catch John Bell Hood's Confederate army. Detaching a portion of his army under George Thomas to defend Tennessee, Sherman reorganized his remaining 62,000 men in four corps into the Army of the Tennessee and the Army of Georgia.
Sherman's two armies cut free from their supply line and headed southeast starting November 15th. The armies made roughly parallel marches on routes planned in advance, including data from the 1860 Census. Part of the army passed through Milledgeville - Georgia's state capital at the time. The Union army cut a swath through the countryside, foraging freely and destroyed infrastructure deemed useful to the war effort such as railroads, cotton, and mills. Sherman hoped to break civilian morale and make Southerners realize the futility of further resistance.
With the main Confederate army having engaged in a futile campaign in Tenneessee, Sherman encountered limited organized resistance until he reached Savannah. Fort McAllister on December 13th and the city surrendered December 21. Sherman famously telegraphed to Lincoln "I beg to present you as a Christmas gift the City of Savannah..."
March Through The Carolinas (aka The Carolinas Campaign)
While the March To The Sea is better known, Sherman was not done. On February 1, 1865, the Union army marched into South Carolina. Columbia, the state capital, fell on February 17th which triggered the evacuation of Charleston. Sherman reached North Carolina in early March with the largest battles of the campaign being fought at Averasborough (Mar 16) and Bentonville (Mar 19-21). Reinforced from the North Carolina coast by Schofield, Sherman captured the state capital at Raleigh on April 13th. The Confederate army under Joe Johnston signed an armistice with Sherman at Durham, NC on April 18; after some complications, Johnson surrendered April 26th.
Battlefields Today
Fort McAllister is now a Georgia State Historic Site. Parts of the Averasborough and Bentonville battlefields have been preserved. All three locations are not far from I-95.
Further Reading
"Decision in the West: The Atlanta Campaign of 1864" by Albert Castel
"Southern Storm: Sherman's March to the Sea" by Noah Andre Trudeau
"Sherman's March Through the Carolinas" by John Gilchrist Barrett