The Fifty-Fifth Illinois Infantry was organized at Camp Douglas, Chicago, and mustered into service October 31, 1861.

It was one of the two Regiments raised by David Stuart, its subsequent Colonel, under Act of Congress, and called the "Douglas Brigade". The other Regiment was the one afterwards known as the famous "Forty-second Illinois". The two Regiments never served together. The Fifty-fifth Illinois was principally made up from bodies of recruits raised in Fulton, McDonough, LaSalle, Grundy, DeKalb, Kane and Winnebago counties, and its members were largely young men raised upon farms.

Left Camp Douglas, November 9, 1861, over the Chicago and Alton railroad for Alton, Illinois, thence by steamboat for St. Louis, and arrived at Benton Barracks, November 11. Remained at Benton Barracks under the immediate command of General W. T. Sherman, until January 12, 1862, when it departed for Paducah, Kentucky, by steamer, which place was reached on January 22. The voyage was a tedious and painful one owing to steamer being frozen into ice and aground for many days.

The Regiment participated in the expedition sent to Columbus, Kentucky, to test the question of its evacuation immediately after the capture of Fort Donelson.

The contest at the latter place was avoided by the Regiment in consequence of the utter worthlessness of its arms before that time issued to it.

On March 8, 1862, the Fifty-fifth embarked on steamer to participate in the movement up the Tennessee River which resulted in the battle of Shiloh, movement on Corinth and etc. On March 15, it landed with other troops at a point several miles above Pittsburg Landing and attempted to cut the railroad in the interior, but this object was defeated by high water.

From that point the expedition dropped down to Pittsburg Landing and went into camp on the front line. It was here brigaded with the Fifty-fourth and Seventy-first Ohio, and Colonel D. Stuart, of the Fifty-fifth, placed in command of the brigade then known as the Second Brigade Fifth (Sherman's) Division. Although belonging to Sherman's Division it was located about two miles east of the other three Brigades of its Division, being in point of fact the extreme left of the army, which met the rebel attack so soon to go into history as the battle of Shiloh.

Prentiss' Division was next to its right and front, though about one mile away. The Fifth-fifth, with its companion regiments, was encamped upon the road leading from Pittsburg Landing to Hamburgh Landing, and near a small branch of Lick Creek.

On the morning of the battle of Shiloh, like all other troops upon the field, it had no premonitions of the fearful conflict to follow, until the report of fire arms further to the right gave evidence of that fact. The Regiment, under the immediate command of Lieutenant Colonel O. Malmborg, formed the center of the brigade, the Seventy-first Ohio being on its right, and the Fifty-fourth Ohio (Zouaves) upon its left. After forming line in several localities contiguous to its camp, during which time it was not engaged except in skirmishing through under the fire of Gage's rebel battery, position was taken to the left of its camp and about sixty rods in its rear along the south edge of a precipitous ravine. During the evolution’s resulting in this formation the Seventy-first Ohio (excepting 18 men and its Adjutant) retreated.

The position of the Regiment at this time was with its right resting at a point precisely 500 yards east of Colonel Stuart's headquarters, with the Fifty-fourth Ohio upon its left. A full half mile of space unoccupied by troops existed to its right, this dangerous interval had been in part caused by the retreat of the Seventy-first Ohio. No artillery was upon this portion of the field to assist the federal troops. The Fifty-fifth Illinois had exactly 512 men in line and the Fifty-fourth Ohio from 350 to 400.

In this position it was finally attacked by Chalmers, and Jackson's Brigades of Bragg's Corps, who had been placed in position at this point under the personal supervision of General Albert Sidney Johnston, the rebel commander-in-chief.

The main attack commenced here about noon, and this position was held until between two and three o'clock P.M., by the two isolated regiments above named, and was of incalculable value to the ultimate success of the Union Army, inasmuch as it defended the extreme left during a vital period from a flank movement contemplated by the rebel order of battle and vigorously attempted at the period spoken of.

After being nearly surrounded and suffering terribly the Regiment retreated from point to point and took its position with its organization still complete in the last line formed in the evening near the Landing. It participated in the battle of Monday, acting on the right, and suffered some loss. During this terrific conflict, the first in its history, the Fifty-fifth lost the heaviest of any federal regiment in that engagement except the Ninth Illinois. The loss of the Fifty-fifth was 1 officer and 51 enlisted men killed and 9 officers and 190 men wounded, being a total of 250 men; 26 men were captured.

The Regiment was engaged in the advance of Corinth and lost 1 killed and 8 wounded on May 17.

Entered Corinth May 30, and moved thence westward with General Sherman, stopping for a greater or less period at Chewalla, Lagrange, Lafayette, Moscow and Holly Springs. On July 21, 1862, the Regiment reached Memphis with General Sherman's Division and remained until November 26, doing camp and picket duty, participating in several expeditions into the interior, having one man wounded. Took part in what was known as the "Tallahatchie" campaign, leaving Memphis November 26, 1862. Returned to Memphis and descended the Mississippi River to take part in the battle of Chickasaw Bayou, where it lost 2 killed and 4 wounded. Was at battle of Arkansas Post January 10 and 11, losing 3 men wounded.

Its first Colonel, David Stuart, who had previously been appointed Brigadier General by the President failed of confirmation and thereupon quit the service in the spring of 1863. Colonel O. Malmborg commanded the Regiment during the balance of its three years term.

April 30, 1863, was with expedition making feint on Haines' Bluff. Thence it proceeded after the army, then making the movement in rear of Vicksburg, overtaking the same in time to be under fire at Champion Hill, suffering no loss. Crossed the Big Black May 17, at Bridgeport, and arrived in front of the works at Vicksburg, May 18. Participated in the assaults of May 19 and 22, and bore its full share during the siege, losing 14 killed and 32 wounded.

It lost 1 man killed while scouting near the Big Black. After being present at the surrender of Vicksburg July 4, the Regiment proceeded with Sherman's expedition to Jackson, wherein it lost 1 killed and two wounded.

Encamped in the vicinity of the Big Black until September 27, 1863, when it embarked at Vicksburg for Memphis and moved thence through Corinth to Iuka. Moved finally across the Tennessee and upon the laborious march to Chattanooga, arriving at that point November 21, 1863. During night of November 23, with rest of brigade, manned fleet of pontoon boats in North Chickamauga Creek and during intense darkness descended and crossed the Tennessee and captured the enemies pickets - one of the most daring operations of the war. At the battle of Mission Ridge, which followed, the Regiment lost 3 wounded.

Marched with Sherman the round trip to the relief of Knoxville. Encamped after return successively at Bridgeport, Bellefonte and Larkinsville, during the winter. While at the latter place after exacting the right to elect officers the Regiment veteranized, at which time the existing field officers all failed of election and at the end of their term quit the service. The veterans were granted 30 days furlough from this point. At the opening of the Atlanta campaign the Regiment took its place as usual in the Second Division of the Fifteenth Corps and shared in the manifold labors and dangers of that famous campaign including the movement on, and battle of Jonesboro, losing 36 killed and 86 wounded, being a total of 122, or about one half of its number engaged.

The heaviest loss was at the assault upon Kenesaw Mountain on June 27, 1864, viz; 14 killed, including its gallant Commander Captain Augustine, and 33 wounded.

Joined in the pursuit of Hood through Northern Alabama and returned to Atlanta, Georgia, where 162 non-veterans were discharged.

Marched the entire distance of the picnic excursion termed the "March to the Sea". Thence north, and lost near Bentonville, N.C., 1 man killed 1 wounded and 6 taken prisoners. After surrender of Johnston, Regiment marched for Washington, via Richmond, and took part in the Grand Review.

The Regiment was then ordered to Louisville, Kentucky, where it remained in camp a few weeks.

Thence moved by steamer to Little Rock, Arkansas, where it was mustered out August 14, 1865. Arrived at Chicago August 22, where it received payment and discharge.

During the entire period of its service it received less than 50 recruits, hence all its casualties were from its original members.

This Regiment was engaged in 31 battles and was 128 days under fire. It marched 3,240 miles, traveled by railroad 2,875 miles and by water a further distance of 5,850 miles, total 11,965 miles.

It lost actually killed in battle 108 men, and its total wounded were 339, making an aggregate of 447 struck with the missiles of war. There are no data to state the exact number of mortally wounded though it is known that 35 died from such cause within one year after "Shiloh". Of the men who actually took the field in battle array more than two out every three were hit by bullets. About one-third of such men lost their lives from the casualties of battle or disease. During the war this Regiment had only 49 men captured which speaks volumes for its discipline and cohesion.

It was extremely fortunate in its medical department, Dr. E. O. F. Roler, of Chicago, being its surgeon in chief.

Its chaplain the Rev. M. L. Haney was all that could be desired, noted as well for his great personal bravery, as for his zealous performance of professional duties.

It is not probable that any other Regiment so closely followed the destiny of General W. T. Sherman. it was first in his brigade at Benton Barracks, in December 1861, and thereafter became a member of the Fifth Division command by that General. Subsequently it was always a member of the Second Division, of the Fifteenth Army Corps, and following all the footsteps of that General, except the Meridian raid. In its various marches it traversed every Southern State except Delaware, Texas and Florida.

Owing to its extraordinary losses at Shiloh and receiving no recruits it was small in numbers at all subsequent periods and noted for its proficiency in drill.

After reorganization at the end of its three years term, it was commanded until nearly the close of its career by its senior captain, when Captain C. A. Andress became Lieutenant Colonel. Its dead now lie buried in nine different States.