More Reading in Bearss’ Vicksburg Campaign, Volume II…
The days after the seizure of Grand Gulf were busy for Grant’s army. Reinforcements were pouring down from the North, freeing troops left on the river to join those who had already crossed. This had to be done quickly, before Pemberton realized that he had more forces in the area than Grant did.
As brigades marched forward, they escorted supply convoys. This meant that Grant could keep more of his force on the line facing Pemberton. In a matter of days, Grant’s three corps were facing Pemberton along 14 Mile Creek, which parallels the railroad south of Edward’s Station. What Grant might have done is a question, but when his right flank corps under McPherson collided with a brigade of Confederate troops under General Gregg, he changed his plans.
The Battle of Raymond was much like Port Gibson – a small force of Confederate troops uses the difficult terrain to advantage for much of the day, before being overwhelmed in the end. While it was nobody’s ideal battle, it was another Union victory. What made it important was that it emphasized to Grant that there were substantial forces gathering at Jackson, which could complicate his attempts to defeat Pemberton at Edward’s Station. These two forces are indicated on the map by the red blotches on the map. If Grant moved against Pemberton at Edward’s Station, the forces at Jackson could move against his flank if he attacked north, or his rear if he tried to drive Pemberton back toward Vicksburg.
Grant decided that Pemberton would be slow to detect a change in plan, since he had watched Grant move toward him at his current position at Edward’s for several days. But if Grant moved quickly off to Jackson, he could scatter the gathering forces there and destroy the railroads in the city, giving him time to turn on Pemberton.
He had McClernand fake a frontal attack while McPherson and Sherman moved on Jackson. Then McClernand retired on Raymond to obstruct any move by Pemberton. This gave Pemberton a chance to fall on McClernand with odds, but the chance was missed, and even so the difficult terrain would have worked in the Union’s favor. Grant now had his army between Pemberton ,and Joe Johnston, who had just been given command the day before Sherman and McPherson took Jackson. The reinforcements who would have at least doubled the size of the Jackson force retired to the east and south, while Johnston fell back to the north. Sherman’s Corps destroyed the industry and railroads around the city, while McPherson joined McClernand facing Pemberton. The chance to catch Grant at a disadvantage was over.
Before leaving Jackson, General Johnston had ordered Pemberton to strike the force threatening Jackson from the west – this would have been McPherson at the time. If only the one corps was involved, this might have been a good enough idea, but Johnston had lost track of the other two corps Even at the time the order was issued, Pemberton would have had to fight McClernand as he advanced. And by the time he got the order, Johnston and all the forces were in full retreat in all directions, and Pemberton was moving alone into a trap.
And Grant knew it, because one of the three couriers delivering the order to Pemberton was a Union spy, who gave it to the Union army even before it got to its intended recipient. Grant was overmatching Pemberton even before he knew what orders he was following – in the battle of Champion Hill to come he held all the cards and he knew it.