General Johnston was preparing to move against Grant's rear on 4 July when he received the sad news that Vicksburg had surrendered. He promptly ordered a retreat to Jackson, which he reached on the 7th. Here he posted his 36,000 men in the line of rifle pits erected earlier under Pemberton's orders. The line was not a particularly strong one, stretching in a westward arc from the Canton Road northwest of town to the Pearl River south of town. Johnston posted Loring's division on the right of his line, Walker and French in the center, and Breckinridge on the left, with cavalry on both flanks.
Johnston's command was pursued by Sherman, who had been guarding Grant's rear from the Big Black River railroad bridge to Haynes' Bluff. Sherman had a makeshift force of 48,000 men, consisting of IX Corps, XIII Corps, XV Corps, one division of XVI Corps and one division of XVII Corps. All together he had twelve divisions under his command, comprising two-thirds of Grant's army.
Sherman's advance forces reached the outskirts of Jackson on the night of 9 July and began skirmishing with Johnston's outposts. He closed in on the city the next day, placing IX Corps on the left, XV in the center and XIII on the right. Sherman felt the enemy lines were too strong to attack head on, so he prepared for a siege, figuring that Johnston did not have enough supplies stored up to hold on for long.
Sharp skirmishing began on the 10th and lasted for several days. Sherman was still in no hurry to direct an assault, though