Which Union general led the March to the Sea and was known for devastating the South by burning Atlanta?

William Tecumseh Sherman is the correct choice because he is most famously associated with the March to the Sea, which took place during the Civil War in 1864. Sherman's campaign aimed to cripple the Confederate war effort by targeting both military and civilian infrastructure. This strategy was exemplified by the burning of Atlanta, a significant Confederacy supply hub, which not only demoralized Southern troops but also aimed to disrupt the livelihoods of the Southern populace.

Sherman's March to the Sea involved a military movement from Atlanta to Savannah, Georgia, where his troops employed tactics of total war, destroying railroads, confiscating food supplies, and burning plantations as they went. This approach was designed to demonstrate the destructive capabilities of Union forces and to hasten the end of the war.

The other figures mentioned played important roles during the Civil War as well but did not lead the March to the Sea or conduct campaigns with the same level of devastation against the Southern infrastructure. George McClellan was known for his cautious approach and for commanding the Army of the Potomac early in the war, Philip Sheridan was renowned for his leadership during the later stages of the conflict, especially in the Shenandoah Valley, and Ulysses S. Grant was the overall Union commander