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.