HEADQUARTERS TRANS-MISSISSIPPI DEPARTMENT, Shreveport, La., June 9, 1863.

General S. COOPER,
Adjutant and Inspector General, Richmond, Va.:

SIR: I have the honor to report, for the information of the War Department, that the column of the enemy under General Banks, after pushing their advance to within 25 miles of Natchitoches, commenced a retrograde movement on the 17th ultimo. One division returned by the Opelousas road to Berwick Bay; the main body, some 20,000 strong, turned off at the Huffpower, and, taking the road to Simsport, crossed under Banks is 32,000 men and eighty-three pieces of artillery. They were reported strongly re-enforced after arriving at Opelousas.

As soon as the movement on Berwick Bay developed itself, I ordered General Walker's division from Pine Bluff, Ark., and the concentration at Niblett's Bluff, on the Sabine, of the disposable force in Texas. The latter force reached the Sabine in time to re-enforce General Mouton, and to operate on the rear and flank of the column which fell back toward Berwick Bay. Owing to the distance and the difficulties encountered, General Walker's column did not reach Red River until the 24th of May. General Banks had then secured his retreat and was crossing the Mississippi.

The practicability of operating against the enemy near Milliken's Bend, and of co-operating with General Pemberton in the defense of Vicksburg, has long occupied my attention. The cutting of the levee above had flooded the country from the Bayou Macon hills to the Mississippi, and, until lately, rendered all operations from West Louisiana impossible.

General Walker was ordered from Arkansas on the 14th of April. Finding he would not arrive before General Banks' retrograde movement had been effected, arrangements were made in advance, and General Taylor was ordered to move rapidly with General Walker's division on the enemy's communications opposite Vicksburg. General Taylor with his command embarked the 29th of May on Catahoula Lake, and, moving by Little River and the Tensas, disembarked opposite Vicksburg on the 2nd instant, and, I believe, is in position to materially assist in the defense of that place. I await with great uneasiness the result of military operations on the Mississippi; especially in the vicinity of Vicksburg does the magnitude of the stake contended for increase my anxiety. Not only the Valley of the Mississippi, but the fate of the Trans-Mississippi Department, is involved in the result. I would throw every man to those points were they disposable. This immense empire is without an army. Were all the troops concentrated, they would scarcely be more than sufficient for operating at any one point threatened; distances are so great that it takes the time of a campaign to re-enforce from one district to another. No effectual concentration can be made at any one district to another. No effectual concentration can be made at any one point without the abandonment of all others. Four brigades of infantry (7,000) were drawn from the district of Arkansas, and are now under Taylor opposite Vicksburg. General Holmes has four brigades of infantry (7,000), besides Marmaduke's cavalry, remaining in his district; he is threatened from Missouri, and is in constant fear of a forward movement of the enemy.