The Battle of Chickasaw Bayou emerged from the Union's broader strategy to capture Vicksburg, Mississippi, which was pivotal for controlling the Mississippi River and the surrounding supply routes. On December 29, 1862, Union General William T. Sherman launched an assault on Confederate positions near Chickasaw Bayou, located just south of the city of Vicksburg. The Confederate forces, commanded by General John C. Pemberton, were well-entrenched and prepared for this offensive. The terrain, characterized by swamps and bayous, presented additional challenges to the Union troops, who struggled to maneuver effectively in the difficult conditions.

As the Union soldiers advanced, they encountered heavy artillery fire and fierce infantry resistance. Pemberton's troops, predominantly composed of local militia and seasoned soldiers, capitalized on the defensive advantages provided by the landscape. The Union forces were unable to break through the Confederate lines, resulting in a decisive repulsion of the Union assault. By the end of the day, the Union Army had sustained significant losses, with estimates suggesting that over 1,700 soldiers had been killed, wounded, or captured.

The failure at Chickasaw Bayou underscored the challenges faced by the Union in their campaign to gain control of Vicksburg and the Mississippi River. This defeat not only curtailed Sherman's immediate objectives but also highlighted the effectiveness of Confederate defensive strategies in this theater of the war. The battle would mark one of several attempts prior to ultimately achieving the Vicksburg Campaign's goals in mid-1863.