The Battle of Chickamauga is significant for marking the end of which Union offensive?

The Battle of Chickamauga, fought in September 1863, is significant as it marked the end of the Chickamauga Campaign, which was an offensive aimed at gaining control of the strategic rail hub in Chattanooga, Tennessee. The campaign involved intense fighting between the Union and Confederate forces and culminated in a notable Confederate victory. This battle showcased the tactical prowess of Confederate General Braxton Bragg against Union General William Rosecrans and resulted in substantial Union casualties, leading to a retreat to Chattanooga.

The outcome of this battle not only halted the Union's advance in the region but also shifted the momentum in favor of the Confederacy for a period of time. The other options refer to different military campaigns that occurred either before or after the Chickamauga Campaign, highlighting their separate significance in the broader context of the Civil War.