HEADQUARTERS ARMY OF THE OHIO,
Nashville, March 23, 1862.

Major General H. W. HALLECK,

Commanding Department of the Mississippi:

GENERAL: If the enemy should contemplate an advance upon Nashville and our position in Middle Tennessee under certain circumstances-a thing which offers very strong inducements-there are three routes by which it could be attempted: First, by the direct route across from Knoxville; second, by the Chattanooga Railroad; third, by the Decatur Railroad.

There are circumstances which render all of them so encouraging to him that I deem it but prudent to take precautions against them, and yet it cannot be done properly without using more troops than I think you can spare from offensive operations between the Tennessee and Mississippi. My arrangements, therefore, hazard something here in order to afford the assistance that will be no doubt needed on the other side of the Tennessee.

I am throwing one division forward to Fayetteville, with one brigade at Murfeesborough to support it if necessary, keep open its communications, and at the same time observe Nashville and the approach from Knoxville; another brigade at Franklin, from which point it can conveniently be diverted to the first objects, if necessary, or be used on the route through Columbia; and another division at and in front of Columbia, either to act with the first division or toward Savannah, according to circumstances.

This, with the necessary bridge and depot guards, will employ a force of about 25,000 men, leaving four divisions, of about 35,000 men or less, for Savannah, with which I will go myself. I shall start from here day after to-morrow, leaving General Dumont in command of the small force immediately about the city and on our lines of communication.

I gather that a considerable force is collecting in East Tennessee, probably already twenty-five or thirty regiments at least, whether for an offensive or defensive object is not yet apparent. I think it sufficient, however, to require an increase of the force in front of Cumberland Gap, and I shall send them all the spare force I can collect in Kentucky, making in that column some ten regiments, two batteries, and some five companies of cavalry. That will, for the present at least, be sufficient to hold a considerable force in check there or penetrate the gap against a weak one, as the case may be. I shall place a good officer there.

I have also intimation, not very well defined yet, of the collection of a considerable force and a large amount of rolling stock about Atlanta. If they should be verified, it is a thing that must be watched. Floyd has gone to Knoxville, leaving Chattanooga with a guard of not more than a few companies. This, in connection with my previous report, will enable you to judge of the propriety of my arrangements.

We are working somewhat in the dark as regards Middle and East Tennessee at least, for we do not know yet what is being done with the Virginia army.

I am trying to get into such shape that we can concentrate wherever it may be necessary.

I have ordered a pontoon bridge for the Tennessee River, to be carried on a light stern-wheel steamer. It will be ready in ten days, and the steamer and bridge will cost about $12,000. We ought to have two