Number 63. Report of Lieutenant Colonel Ezekiel S. Sampson, fifth Iowa Infantry, THIRD Brigade, including operations since April 25. HEADQUARTERS FIFTH IOWA INFANTRY, Before Vicksburg, MISS., May 25, 1863.

CAPTAIN: I have the honor to submit through you, to the colonel commanding this brigade, the following report of the part taken by this regiment in our recent marches and engagements:

On the 25th of April, 1863, we left Milliken's Bend La., reaching Sargent' plantation after two days' march a distance of 30 miles, where we remained one, day, and on the 28th resumed the march, reaching Perkin's Landing, below Carthage, on the 29th. The bad condition of the roads from Milliken's Bend to Perkin's Landings, and our limited means of transportation, rendered it necessary to send back teams each night each morning. Marching over bad roads, under a scorching sun, and with heavy knapsacks, after so long inactive, exhausted many of my when I also managed to bring forward each night in ambulances.

On the 30th, we remarched from Perkin's Landing to Hard Times Landing and mustered on the night of the 30th.

On the 1st of May, I took my regiment on board the gunboat Pittsburg, crossed the Mississippi River to Bruinsburg, MISS, and marched the same day 9 miles into the interior, in the direction of Port Gibson, which place, we reached at noon on the 2nd of MAY, and CAMPED ON Willow Bayon, 8 miles distant, same night.

On the 3rd, after crossing Willow bayou, our advance was checked by a battery of the enemy in front. Our brigade was formed in line of battle on right of the road, my regiment supporting the Tenth Iowa Infantry, deployed as skirmishers in our front. Intelligence of the fight of the enemy was soon brought us, and we resumed our line of march, reaching Big Black same night.

On the 5th, made reconnaissance with my regiment in company with the Tenth Iowa Infantry, three companies of cavalry and two pieces of artillery, the whole under command of Colonel Boomer. My regiment being in advance the stream, I threw out two companies as skirmishers, and pushed them forward, supported by my regiment, some 5 miles in the direction of Vicksburg, until I came upon the enemy in force, occupying a high range of hills in our front, when I was ordered to fall back, and recrossed Big Black to our former camp. The reconnaissance was entirely successful and satisfactory, without singe casualty.

On the 9th, we resumed the march in the direction of Jackson, MISS. Reaching Raymond on the 12th.]

On the 13th, resumed march on road leading through Clinton, and my regiment being in advance came upon the pickets of the enemy, and after a sharp skirmish, drove them from their position. I continued to advance my skirmishers until they reached and occupied Clinton, about 4 p. m. when we halted for a few hours, and camped at night from latter place about 2 miles, on the road to Jackson.

On the 14th marched at 8 a. m., and after a few miles' march in a drenching rain, were brought to a halt by the enemy in front, who were found in force occupying the height about 3. 1/2 miles from Jackson. Our