4th Infantry Regiment, organized at New Orleans, Louisiana in April, 1861, contained men from New Orleans and the parishes of St. Helena, Lafourche, West Feliciana, Plaquemines, West Baton Rouge, and East Carroll. The unit served on the gulf coast of Louisiana and Mississippi, then moved to Tennessee where it was engaged in the fight at Shiloh. Later it was assigned to Maxey's Brigade, Department of Mississippi and East Louisiana. It saw action at Vicksburg and Baton Rouge, and was on duty at Port Hudson. until March, 1863. Sent to Jackson and later Mobile, it then was assigned to Quarles' and Gibbon's Brigade. The regiment participated in the Atlanta and Hood's Tennessee campaigns, and in 1865 returned to Mobile. It sustained 209 casualties at Shiloh, had 403 present for duty in July, 1862, totalled 374 men and 391 arms in December, 1863, and had 161 fit for duty in November, 1864. The 4th was included in the surrender on May 4, 1865.
The field officers were Colonels Henry W. Allen, Robert J. Barrow, and S. E. Hunter, Lieutenant Colonel William F. Pennington, and Majors E. J. Pullen and Thomas E. Vick.