The first work of the regiment was on the advance on Port Hudson, March 10, 1863, when Colonel Bissell, in command of his own regiment, two detachments of cavalry and a regular army battery, occupied Bayou Montesano, constructed earthworks and built a bridge across Bayou Sara. This bridge was designed by Sergeant William Webster of Company I, after a West Point engineer had despaired of the job. The regiment was seven miles in advance of the rest of the army and in a very exposed and dangerous position. This position they held under a frequently severe fire till the remainder of the army came up when they joined the column and went on to Port Hudson. They were in the front of the land forces when Farragut sailed by the forts in the Flagship Hartford. From the banks of the river the Twenty-fifth witnessed this grand bombardment and the burning of the frigate Mississippi in the night. When the object of the expedition had been accomplished (to use the words of General Banks' order), the regiment returned to Baton Rouge, passing a wet and dreary night in Camp Misery, a night which will never be forgotten, nor will any one ever forget the noble act of Quartermaster John S. Ives, who rode his tired horse several miles to Baton Rouge and brought out to the men coffee, which they managed to prepare over small fires and which no doubt saved many a man's life. After a short stay at Baton Rouge, the army made another advance on the west bank of the Mississippi, starting March 28th, 1863, marching with frequent skirmishes, sailing up the Atchafalaya bayou and landing at Irish Bend, where the regiment engaged in its first real battle, April 14th, 1863. The severity of this battle may be judged of as we read in the Adjutant-general's report: "Our loss, as you will see from the accompanying returns of the casualties has been very severe, being in all, ninety-six killed and wounded out of 350 with which the regiment went into action." From this point the regiment marched up to within six miles of the Red River and of this march the regimental report speaks thus: "What with our loss in battle, details for special service and the number who have given out on our very long and severe marches, this regiment is much reduced and has today only 299 men present of whom but 248 are fit for duty. You will thus see, though this campaign has been eminently successful, driving the enemy before us through the entire valley of the Teche, from its mouth to its source, it has been very trying upon the troops. Four engagements and 300 miles march in twenty days call for proportionate suffering which cannot be avoided."