This river wing was now depleted of some excellent troops and
again divided into quite separate commands. Buell commanded the
Army of the Ohio. Grant commanded his own Army of the Tennessee
and Rosecrans's Army of the Mississippi. Buell's scene of action
lay between the tributary streams--Ohio, Cumberland, and
Tennessee--with Chattanooga as his ultimate objective. Grant's
scene of action lay along the southward rails and Mississippi,
with Vicksburg as his ultimate objective.

The Confederates were of course set on recovering complete
control of the line of Southern rails that made direct
connections between the Mississippi Valley and the sea: crossing
the western tributaries of the St. Francis and White Rivers; then
running east from Memphis, through Grand Junction, Corinth, and
Iuka, to Chattanooga; thence forking off northeast, through
Knoxville, to Washington, Richmond, and Norfolk; and southeast to
Charleston and Savannah. Confederate attention had originally
been fixed on Corinth and Chattanooga. But General O. M.
Mitchel's abortive raid, just after Shiloh, had also drawn it to
the part between. The Federals therefore found their enemy alert
at every point.

Braxton Bragg, Beauregard's successor and Buell's opponent,
basing himself on Chattanooga, tried to drive his line of
Confederate reconquest through the heart of Tennessee and thence
through mid-Kentucky, with the Ohio as his ultimate objective.
His colleagues near the Mississippi, Van Dorn and Sterling Price,
meanwhile tried to effect the reconquest of the Memphis-Corinth
rails that Grant and Rosecrans were holding.