Final answer:
The song was written for the Union side and celebrates Sherman's March to the Sea.
Step-by-step explanation:
This song was written for the Union side, and you can tell because it celebrates Sherman's March to the Sea. Sherman's March to the Sea was a military campaign by the Union Army during the American Civil War aimed at demoralizing the Confederates. The song's celebration of this campaign is an indication that it is a union song.