The battle Hostile_encounter was fought Hostile_encounter between the Army of the Cumberland under Maj. Gen. William Rosecrans and the Confederate Army of Tennessee under Gen. Braxton Bragg , and was named Name_conferral for Chickamauga Creek , which meanders near the battle Hostile_encounter area in northwest Georgia ( and ultimately flows Motion into the Tennessee River about 3.5 miles ( 5.6 km ) northeast of downtown Chattanooga ) .

After his successful Tullahoma Campaign Military_operation , Rosecrans renewed Recovering the offensive , aiming Aiming to force Causation the Confederates out of Chattanooga .

In early September , Rosecrans consolidated Cause_change_of_strength his forces Causation scattered Dispersal in Tennessee and Georgia and forced Causation Bragg 's army out of Chattanooga , heading Self_motion south .

Bragg was determined Deciding to reoccupy Conquering Chattanooga and decided Deciding to meet Come_together a part of Rosecrans 's army , defeat Conquering it , and then move back Self_motion into the city .

Union forces Causation then retired Escaping to Chattanooga while the Confederates occupied Control the surrounding Surrounding heights , besieging Besieging the city .