Having been outflanked from Chattanooga and forced to withdraw into Georgia by the northern Army of the Cumberland commanded by Gen Rosecrans, Gen Bragg and the reinforced Confederate Army of Tennessee sought to defeat their opponents in detail before attempting to recapture Chattanooga. On 18 September—as the Army of the Cumberland began concentrating in a heavily wooded region along the LaFeyette-Chattanooga Road on the northwest side of Chickamauga Creek in Northern Georgia—Bragg’s vanguard managed to capture several crossing points from Federal cavalry across the creek at Alexander’s Bridge and Reed’s Bridge. The main fighting began on 19 September in the northern flank of both armies near Jay’s Mill. Throughout the day, both armies continuously reinforced their Northern flanks, and the Confederate forces eventually pushed the Union army back toward the LaFeyette-Chattanooga Road. The heavily wooded terrain of the battlefield hindered the commanders’ ability to maintain command and control over their forces, making it difficult to coordinate efforts. By the morning of 20 September, the Army of the Cumberland defended an entrenched position along the road, from which they were able to repel several Confederate assaults earlier in the day. However, miscommunication between Union commanders created a quarter-mile gap in their defenses, which was violently exploited by Confederate Gen Longstreet. Consequently, the Army of the Cumberland collapsed and began to flee from the battlefield, and only the determined rearguard defense of Gen Thomas’s men on Snodgrass Hill prevented the total disintegration of Rosecrans’s army. Confederate casualties from the battle numbered over 18,000 compared to the 16,00 suffered by Union forces. The Army of the Cumberland retreated to Chattanooga, while the Army of Tennessee occupied the heights overlooking the city—thus setting the stage for the Siege of Chattanooga.