The morning of the 19th September opened with Thomas reacting to an inaccurate situation report from Dan McCook.

Rosecrans’ post battle report Thomas moves on Reed’s Bridge Map 1 The battle opens Map 2 Liddell attacks Support from Cheatham

The map below shows the situation around Reed’s Bridge in the very early hours of the morning of the 19th.  The map has been rotated, so that north is on the left of the map.

Early on the morning of the 19th McCook was ordered back to Rossville by Granger, and en-route, at the Lafayette road he met Thomas who had just completed his move up from Crawfish Springs. McCook then gave the situation report to Thomas, as he saw it; a single Confederate infantry brigade was on the west side of the bridge, with the bridge destroyed behind them.

From Thomas’ post battle report; “Col. Dan McCook, commanding a brigade of the Reserve Corps, met me at General Baird’s headquarters, and reported to me that he had been stationed the previous night on the road leading to Reed’s bridge, and that he could discover no force of the enemy except one brigade, which had crossed to the west side of the Chickamauga at Reed’s Bridge the day before; and he believed it could be cut off, because, after it had crossed, he had destroyed the bridge, the enemy having retired toward Alexander’s Bridge.  Upon this information I directed General Brannan to post a brigade, within supporting distance of Baird, on the road to Alexander’s Bridge, and with his other two brigades to reconnoiter the road leading to Reed’s bridge to see if he could locate the bridge reported by Colonel McCook, and, if a favorable opportunity occurred, to capture it. His dispositions were made according to instructions by 9 am.”

This situation was not correct, but was as McCook understood it. This was an opportunity that Thomas could not afford to pass up, but he was unaware that Bushrod Johnson and Walker were on the west side of the Chickamauga, ready to attack southward as required by Bragg’s battle plan.

From Rosecrans’ post battle report

At this point Colonel McCook, of General Granger's command, who had made a reconnaissance to the Chickamauga the evening before and had burned Reed's Bridge, met General Thomas, and reported that an isolated brigade of the enemy was this side of the Chickamauga, and, the bridge being destroyed, a rapid movement in that direction might result in the capture of the force thus isolated.

General Thomas ordered Brannan with two brigades to reconnoiter in that direction and attack any small force he should meet. The advance brigade, supported by the rest of the division, soon encountered a strong body of the enemy, attacked it vigorously, and drove it back more than half a mile, where a very strong column of the enemy was found, with the evident intention of turning our left and gaining possession of the La Fayette road between us and Chattanooga.

Thomas’ position was well secured so he ordered Brannan, who commanded his left division, to move on Jay’s Mill and take advantage of the situation. Brannan sent Croxton’s brigade off on the Alexander’s Bridge road, with Van Derveer’s brigade on the left on the Reed’s Bridge road.  Now, where Bragg believed that he overlapped the Federal left, he was in fact himself overlapped by Rosecrans’ forces under Thomas.  Again, as so often during these three days, each was unaware of the positions of the other army’s flanks. 

The map below shows the dispositions as Thomas moved his forces against the expected single Confederate brigade west of Reed’s Bridge.

At around 07:30 Brigadier General Davidson’s Confederate cavalry, part of Forrest’s Cavalry Corps, came into contact with Croxton’s skirmishers, and routed them back to their main force.  In their turn, Davidson’s cavalry were routed by Croxton’s main force but Forrest rallied the men and the battle with Croxton’s five regiments was now on.  However, Forrest knew that he needed additional strength, and rode off to Alexander’s Bridge where he met Bragg and Walker, who gave him Wilson’s brigade. Wilson, hitting Croxton’s right flank, caused Croxton to change his front to protect his right. On the Federal left, Forrest had deployed Dibrell’s brigade, who then came into contact with Van Derveer and were brought to a halt. At this point Forrest commandeered Brigadier General Ector’s brigade from Walker’s force, without informing Walker.  By now, around midmorning, Forrest had stabilized his Confederate line, and Brannan’s division had realised that they were up against two Confederate divisions. This was not the plan when Thomas had sent them east to Reed’s Bridge. Reinforcements were needed, and Thomas released Baird’s division along the Alexander’s Bridge road towards Croxton’s force. They arrived around 10:30, Croxton, low on ammunition, pulled back and Starkweather’s brigade of Baird’s division took their position.

The ground over which the troops were fighting was covered with scrub and vegetation, making it difficult to see friends as well as enemies, and so again the lack of information regarding other forces would cause surprise.  Baird moved against Wilson’s and Ector’s brigades at around 11:00, but did not pursue this vigorously as he became aware of a force on his right, and caused Big. Gen. King to change his front to meet this possible threat to his right. The threat would come from Liddell’s division. 

The map shows the attack by Liddell’s brigades.

Liddell had formed up the brigades of Waltham and Govan on the Alexander’s Bridge road and then sent them forward against Baird’s right flank. It was a devastating blow.  King’s brigade was caught by Govan’s brigade while trying to reform to face the threat from the right, and Waltham hit Scribner’s brigade. Both brigades broke, and most of their guns were captured.  Liddell now struck at Connell’s brigade, which had not broken when they saw the flight of Baird’s men, Starkweather’s brigade was also hit, but they broke and had their guns captured. At this point Van Derveer’s men had only had little involvement and were in a good condition to meet the attack from Liddell’s men. By this point in the battle the Confederates had delivered a severe blow to the Federal left, they had captured a number of guns and forced a number of brigades to break and run. Not surprisingly, having had to march up to support Walker’s force, and then smash into Baird’s division, Liddell’s men were fatigued. When Van Derveer’s force fired their volleys, almost in the faces of Liddell’s men, the Confederates withdrew. As the Federals moved forward they recovered the guns they had previously lost.

  Unfortunately the support that the Confederates now needed at this point to make the decision conclusive, was not there, and had they been able to see through the thick scrub they would have seen Federal forces arriving towards both of their flanks. Richard Johnson’s division from McCook’s Corps had been ordered by Thomas to go in on Baird’s right, while the re-formed elements of Baird’s and Brennan’s divisions, including Croxton, were rejoining in the centre and the left.

Bragg had another large force at his disposal against Thomas.  Major General Cheatham commanded the the largest division in the Army of Tennessee, its five brigades were part of Polk’s corps and around 07:00 that morning they had crossed the Chickamauga at Dalton’s Ford, some way south of Alexander’s Bridge.  They had then been ordered north by Bragg at around 11:00, while Baird’s force was attacking Ector and Wilson.  They arrived in time to form on the left of Liddell’s division while it was withdrawing in front of Van Derveers volleys.  Cheatham formed up with his five brigades in two lines; in the front were the brigades of Brig. Gen. Wright on the left, Brig. Gen. Smith in the centre and Brig. Gen. Jackson on the right.  Behind them were Brig. Gen. Strahl and Maney. It was now around noon.