On the 13th of December the regiment started for the south, stopping for a few days at Cairo, Columbus and at Jackson, Tennessee, marching from there to Trenton. Here two brigades were organized to move against General Forrest. Colonel C. L. Dunham of the Fiftieth Indiana commanded the Union forces which included the Thirty-ninth Iowa. On the 27th of December he marched eastward with 1,600 men and on the fourth day came suddenly upon Forrest’s army 6,000 strong, drawn up in battle array at Parker’s Cross Roads, a few miles south of Clarksville. The battle at once began and was carried on with varying success for several hours, the little Union army holding its position with great bravery until General Sullivan came up with heavy reinforcements, when the Confederates were routed. The Thirty-ninth was under heavy fire for several hours and fought bravely. Misapprehending an order at one stage of the battle, the regiment was temporarily thrown into confusion but soon rallied and regained its place in the line. Lieutenant-Colonel Redfield and Captain Cameron, Major Griffiths and Adjutant Tichenor were conspicuous for gallantry. The loss of the regiment was four killed, thirty-three wounded and eleven missing. Among the wounded were Lieutenant-Colonel Recifield, Major Griffiths, Captain Brown and Lieutenant Rawles. On the 29th about one hundred men of the regiment, worn out on the march in attempting to return to Trenton, were captured at Shady Grove and suffered an imprisonment of nearly ten months.

In January, 1863, the regiment moved to Corinth and was there assigned to the Third Brigade in the division commanded by General G. M. Dodge of Iowa. Headquarters were in Corinth for nearly a year, with an occasional march into the adjacent country. The regiment was with Colonel Streight in his raid into Alabama, returning to Corinth. Company H in April being sent a few miles from Corinth to guard a corral, was surrounded by several hundred of the enemy’s cavalry, the captain and most of his men captured. During the remainder of the year the regiment was employed in Tennessee guarding lines of railroad and similar duties. In the spring of 1864, the Thirty-ninth joined Sherman’s army at Gordon’s Mills, and from this time until it reached Kingston our regiment marched and fought on the right wing. It led the army in the flanking movement by Calhoun, which caused the evacuation of Resaca by the Confederates. Here it was engaged with superior numbers and was extricated from a position of great peril by the arrival of reinforcements.

The regiment remained at Rome doing garrison duty until October when, joining the forces under General John M. Corse, it participated in the brillant defense of Allatoona. General Hood in command of the Confederate army was now moving northward and sent a force of cavalry to cut Sherman’s communication near Marietta, while with the main army he crossed the Chattahoochee and marched on Dallas. A large force of the enemy, after destroying the railroad at Big Shanty, moved against Allatoona Pass, where there were immense stores of rations for Sherman’s army guarded by the Ninety-third Illinois under Lieutenant-Colonel Tourtelotte. General John M. Corse was at Rome with his division. General Sherman signaled him to reinforce Allatoona Pass and hold it at all hazards. Early on the morning of October 5th Corse was there with 2,000 men, including the Thirty-ninth Iowa under Lieutenant-Colonel Redfield. Soon after daylight General French had the works completely invested and sent Corse a summons to surrender, which was promptly declined. An assault was then ordered and the Confederate army rushed upon the outer works with the utmost fury. A deadly fire was opened upon them by the garrison making great gaps in their lines which were promptly filled, and one of the most deadly combats of the war ensued. The enemy charged by regiments and brigades and the struggle over the rifle pits and outer works was of the most desperate character. 

After three hours of hard fighting Sherman became anxious as to the result and signaled from mountain top to mountain top" Hold the fort, I will help you." Corse signaled back his grim reply and the battle increased in fury. Having failed to break our lines by repeated charges of brigades the Confederates now came on in mass. Wrought up to the highest pitch of desperation on both sides the combat became of the most deadly nature. Men bayonetted each other over the rifle pits and officers thrust their swords into the bodies of their foes. Corse received a severe wound in his face and became insensible, when Colonel Rowell of the Seventh Illinois assumed command and directed the battle with skill and courage until he, too, fell severely wounded. Corse having revived, now resumed command and the garrison was driven into two forts. At two o’clock the crisis of the hard-fought battle came. The garrison was weakened by long hours of the most desperate fighting and the loss of many brave men, but there was no thought of surrender. The Confederates now formed in compact masses for another assault. Our gunners double-shotted their field pieces and waited until the enemy was within a few paces, then opened upon the crowded ranks with grape and canister. Nothing could stand against the deadly missiles; staggered and confused they halted, then broke and finally turned and fled. The great victory was won but at a fearful cost. More than seven hundred of the brave defenders fell in the heroic struggle.

No regiment at Allatoona Pass fought with greater gallantry than the Thirty-ninth Iowa. In the early part of the battle it was posted some three hundred yards from the principal forts which had been constructed for the defense of the place. Here the enemy made the most determined attacks which were several times repulsed. At length the regiment fell slowly back to cover of the forts, where it fought with courage and obstinacy never surpassed. The losses in killed, wounded and captured were one hundred and sixty-five and among the slain was the heroic commander, Lieutenant-Colonel James Redfield. He was first wounded in the foot but retained his command; a second shot shattered his leg but he still refused to leave his post, and directed the fight encouraging his men by example and words to hold their ground. A third ball pierced his heart and Iowa lost one of its noblest and bravest officers. Lieutenants O. C. Ayers, A. T. Blodgett, N. P. Wright and J. P. Jones were also killed and O. D. Russell was severely wounded.