Vicksburg was important to the enemy because it occupied the first high ground coming close to the river below Memphis. From there a railroad runs east, connecting with other roads leading to all points of the Southern States. A railroad also starts from the opposite side of the river, extending west as far as Shreveport, Louisiana. Vicksburg was the only channel, at the time of the events of which this chapter treats, connecting the parts of the Confederacy divided by the Mississippi. So long as it was held by the enemy, the free navigation of the river was prevented. Hence its importance. Points on the river between Vicksburg and Port Hudson were held as dependencies; but their fall was sure to follow the capture of the former place.
The campaign against Vicksburg commenced on the 2d of November as indicated in a dispatch to the general-in-chief in the following words: "I have commenced a movement on Grand Junction, with three divisions from Corinth and two from Bolivar. Will leave here [Jackson, Tennessee] to-morrow, and take command in person. If found practicable, I will go to Holly Springs, and, may be, Grenada, completing railroad and telegraph as I go."
At this time my command was holding the Mobile and Ohio railroad from about twenty-five miles south of Corinth, north to Columbus, Kentucky; the Mississippi Central from Bolivar north to its junction with the Mobile and Ohio; the Memphis and Charleston from Corinth east to Bear Creek, and the Mississippi River from Cairo to Memphis. My entire command was no more than was necessary to hold these lines, and hardly that if kept on the defensive. By moving against the enemy and into his unsubdued, or not yet captured, territory, driving their army before us, these lines would nearly hold themselves; thus affording a large force for field operations. My moving force at that time was about 30,000 men, and I estimated the enemy confronting me, under Pemberton, at about the same number. General McPherson commanded my left wing and General C. S. Hamilton the centre, while Sherman was at Memphis with the right wing. Pemberton was fortified at the Tallahatchie, but occupied Holly Springs and Grand Junction on the Mississippi Central railroad. On the 8th we occupied Grand Junction and La Grange, throwing a considerable force seven or eight miles south, along the line of the railroad. The road from Bolivar forward was repaired and put in running order as the troops advanced.
Up to this time it had been regarded as an axiom in war that large bodies of troops must operate from a base of supplies which they always covered and guarded in all forward movements. There was delay therefore in repairing the road back, and in gathering and forwarding supplies to the front.
By my orders, and in accordance with previous instructions from Washington, all the forage within reach was collected under the supervision of the chief quartermaster and the provisions under the chief commissary, receipts being given when there was any one to take them; the supplies in any event to be accounted for as government stores. The stock was bountiful, but still it gave me no idea of the possibility of supplying a moving column in an enemy's country from the country itself.