The Union armies were now divided into nineteen departments, though four of them in the West had been concentrated into a single military division.  The Army of the Potomac was a separate command and had no territorial limits.  There were thus seventeen distinct commanders.  Before this time these various armies had acted separately and independently of each other, giving the enemy an opportunity often of depleting one command, not pressed, to reinforce another more actively engaged.  I determined to stop this.  To this end I regarded the Army of the Potomac as the centre, and all west to Memphis along the line described as our position at the time, and north of it, the right wing; the Army of the James, under General Butler, as the left wing, and all the troops south, as a force in rear of the enemy.  Some of these latter were occupying positions from which they could not render service proportionate to their numerical strength.  All such were depleted to the minimum necessary to hold their positions as a guard against blockade runners; where they could not do this their positions were abandoned altogether.  In this way ten thousand men were added to the Army of the James from South Carolina alone, with General Gillmore in command.  It was not contemplated that General Gillmore should leave his department; but as most of his troops were taken, presumably for active service, he asked to accompany them and was permitted to do so.  Officers and soldiers on furlough, of whom there were many thousands, were ordered to their proper commands; concentration was the order of the day, and to have it accomplished in time to advance at the earliest moment the roads would permit was the problem.

As a reinforcement to the Army of the Potomac, or to act in support of it, the 9th army corps, over twenty thousand strong, under General Burnside, had been rendezvoused at Annapolis, Maryland.  This was an admirable position for such a reinforcement.  The corps could be brought at the last moment as a reinforcement to the Army of the Potomac, or it could be thrown on the sea-coast, south of Norfolk, in Virginia or North Carolina, to operate against Richmond from that direction.  In fact Burnside and the War Department both thought the 9th corps was intended for such an expedition up to the last moment.

My general plan now was to concentrate all the force possible against the Confederate armies in the field.  There were but two such, as we have seen, east of the Mississippi River and facing north.  The Army of Northern Virginia, General Robert E. Lee commanding, was on the south bank of the Rapidan, confronting the Army of the Potomac; the second, under General Joseph E. Johnston, was at Dalton, Georgia, opposed to Sherman who was still at Chattanooga.  Beside these main armies the Confederates had to guard the Shenandoah Valley, a great storehouse to feed their armies from, and their line of communications from Richmond to Tennessee.  Forrest, a brave and