After the battle of Shiloh, the Thirteenth Iowa was assigned to the Third Brigade of the Sixth Division. The Brigade was composed of the Eleventh, Thirteenth, Fifteenth and Sixteenth regiments of Iowa Infantry, and was under command of Colonel Crocker.
Following the Battle of Shiloh, the Thirteenth Iowa was assigned to the Third Brigade of the Sixth Division. The Brigade included the Eleventh, Thirteenth, Fifteenth, and Sixteenth regiments of Iowa Infantry, which were all part of a larger unit under Colonel Crocker.