Learning from the instructions and other papers turned over to me by General Sherman that you had promptly and generously co-operated to insure the success of the Mississippi River Expedition, and would be pleased, under favorable circumstances, to have his co-operation in turn, I immediately determined to sail with my whole army to the Post of Arkansas via the mouth of the White River, the cut-off, and the Arkansas River, for the purpose of reducing it.

The reduction of that place will free the navigation of the Mississippi River in the vicinity of the mouths of the White and Arkansas Rivers from the molestation inflicted by hostile parties sent from the Post.

Whether I will advance beyond the Post to to Brownsville and Little Rock, or to either, will depend upon circumstances yet undeveloped.

If, as I understand, your columns are moving in the direction of the last-named places, a favorable conjuncture may conspire to give our arms early, if not immediate, control of the State of Arkansas.

Hoping to hear from you fully and frankly upon all matters of public interest, I have the honor to conclude by assuring you of my high regard for you, both personally and officially.

Your obedient servant,

JOHN A. McCLERNAND,

Major-General, Commanding.

HEADQUARTERS ARMY OF THE MISSISSIPPI,
Steamer Tigress, January 8, 1863.

Major General U. S. GRANT,

Commanding Department of the Tennessee:

When I arrived at the mouth of the Yazoo River I found that our army, having been repulsed near Vicksburg, was re-embarked under General Sherman's order for conveyance to Milliken's Bend, on the Mississippi River.

On the next day, the 4th, while the troops were still on the transports, I assumed command of the land forces of the Mississippi River Expedition and immediately determined, with the co-operation of Admiral Porter, to sail with my whole command for the Post of Arkansas via the mouth of White River, the cut-off, and the Arkansas River, for the reduction of that Post.

I am now here and will immediately resume my voyage to the appointed destination. The reasons justifying and requiring this movement may be stated as follows:

1st. The failure of the Mississippi River Expedition in the object of reducing Vicksburg and the present impracticability of reducing that place with the force under my command by a front attack unsupported by a co-operative movement in the rear of the place.

2d. The importance, nay duty, of actively and usefully employing our arms not only for the purpose of subduing the rebellion but to secure some compensation for previous expense and loss attending the expedition.

3d. The importance of reducing the Post as a means of freeing the navigation of the Mississippi River in the vicinity of the mouths of White and Arkansas of making a diversion of the enemy, who are alleged to be marching to certain points in Missouri, and of co-operating with General Curtis' column in Arkansas.

5th. The counteraction of the moral effect of the failure of the attack