The regiment lost 5 officers and 86 enlisted men who were killed in action or who died of their wounds and 2 officers and 166 enlisted men who died of disease, for a total of 259 fatalities.

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.

This organization remained intact until the close of the war.

Except when upon detached duty, the operations of each of the regiments were identified very largely with those of the brigade, and, therefore, the history of each of these four Iowa regiments is almost inseparably interwoven with that of the brigade.