at that stopped only at
Chattanooga, south of the Tennessee River, which, with the surrounding
mountains, made it the strategical center and military key to the heart
of Georgia and the South. This march of Rosecrans, ending the day before
the Vicksburg surrender, again gave the Union forces full possession of
middle Tennessee down to its southern boundary.

The march completed, and the enemy thus successfully manoeuvered out of
the State, Rosecrans once more came to a halt, and made no further
movement for six weeks. The President and General Halleck were already
out of patience with Rosecrans for his long previous delay. Bragg's
retreat to Chattanooga was such a gratifying and encouraging supplement
to the victories of Vicksburg and Port Hudson, that they felt the
Confederate army should not be allowed to rest, recruit, and fortify the
important gateway to the heart of the Southern Confederacy, and early
in August sent Rosecrans peremptory orders to advance. This direction
seemed the more opportune and necessary, since Burnside had organized a
special Union force in eastern Kentucky, and was about starting on a
direct campaign into East Tennessee.

Finally, obeying this explicit injunction, Rosecrans took the initiative
in the middle of August by a vigorous southward movement. Threatening
Chattanooga from the north, he marched instead around the left flank of
Bragg's army, boldly crossing the Cumberland Mountains, the Tennessee
River, and two mountain ranges beyond. Bragg, seriously alarmed lest
Rosecrans should seize the railroad communications behind him, hastily
evacuated Chattanooga, but not with the intention of flight, as
Rosecrans erroneously believed and reported. When, on September 9, the
left of Rosecrans's army marched into Chattanooga without firing a shot,
the Union detachments were so widely scattered in separating mountain
valleys, in pursuit of Bragg's imaginary retreat, that Bragg believed he
saw his chance to crush them in detail before they could unite.

With this resolve, Bragg turned upon his antagonist but his effort at
quick concentration was delayed by the natural difficulties of the
ground. By September 19, both armies were well gathered on opposite
sides of Chickamauga Creek, eight miles southeast of Chattanooga; each
commander being as yet, however, little informed of the other's position
and strength. Bragg had over seventy-one thousand men; Rosecrans,
fifty-seven thousand. The conflict w