Halleck has accomplished little following Corinth, while Confederate General Braxton Bragg had succeeded Beauregard (on June 27, for health reasons) in command of his fifty-six thousand troops of the Army of Tennessee, in Tupelo, Mississippi, due south of Corinth, but had determined that an advance directly north from Tupelo was not practical.

Leaving Major Generals Sterling Price and Earl Van Dorn to distract Grant, he shifts thirty-five thousand men by rail through Mobile, Alabama, to Chattanooga.

While Buell is facing Bragg's threat in Kentucky, Confederate operations in northern Mississippi ire aimed at preventing Buell's reinforcement by Grant, who is preparing for his upcoming Vicksburg campaign.

Halleck had departed for Washington, and Grant has been left without interference as commander of the District of West Tennessee.

On September 14, Major General Sterling Price moves his Confederate Army of the West to Iuka, twenty miles (thirty-two kilometers) east of Corinth.

He intends to link up with Major General Earl Van Dorn's Army of West Tennessee and operate against Grant, but Grant sends forces under Major Generals William S. Rosecrans and Edward Ord to attack Price's force at Iuka.

General William Rosecrans wins a minor victory at the Battle of Iuka on September 19, but poor coordination of forces and an acoustic shadow allow Price to escape from the intended Union double envelopment.

Major Generals Sterling Price and Earl Van Dorn decide to unite their forces and attack the concentration of Union troops at Corinth, then advance into West or Middle Tennessee.

In the Second Battle of Corinth (October 3–4), they attack the fortified Union troops but are repulsed with serious losses.

Retreating to the northwest, they escape pursuit by Rosecrans's exhausted army, but their objectives of threatening Middle Tennessee and supporting Bragg have been foiled.

Union ironclad gunboat USS Cairo is sunk by a remotely-detonated "torpedo" (naval mine) while clearing mines from the Yazoo River  for the attack on Haines Bluff, becoming the first armored ship sunk by  by a mine remotely detonated by hand, on December 12, 1862.

Grant's first campaign is a two-pronged movement.

William T. Sherman sails down the Mississippi River with thirty-two thousand men while Grant is to move in parallel through Mississippi by railroad with forty thousand.

Grant advances eighty miles (one hundred and thirty kilometers), but his supply lines are cut by Confederate cavalry under Earl Van Dorn at Holly Springs, forcing him to fall back.

Union General William T. Sherman reaches the Yazoo River just north of the city of Vicksburg, but without support from Grant's half of the mission, he is repulsed in bloody assaults against Chickasaw Bayou from December 26 to 29.

This victory for the Confederate Army, here outnumbered two to one, results in six times as many Union casualties.