On June 6, 1863, the regiment left for Vicksburg, Mississippi, a Confederate stronghold, as part of Major General Francis Herron's Division.

The 38th Iowa Infantry arrived on June 11, 1863, in the vicinity of Vicksburg, where the Union Army of the Tennessee under Major General Ulysses S. Grant was besieging the city.

In response to rumors of Confederate cavalry moving from Yazoo City, Mississippi, Herron's Division was ordered to a position on the southernmost portion of Grant's line.

On June 15, the 38th Iowa Infantry took a position on the extreme left of the line, extending from the river to a short distance across the Warrenton Road.

[1] On April 9, 1865, the consolidated 34th Iowa Infantry participated in the last major battle of the Civil War at Fort Blakeley, Alabama.