Tightening the Siege
After the unsuccessful assaults of May 19 and May 22, 1863, Maj. Gen. Ulysses S. Grant reluctantly settled into a siege. Historian Shelby Foote wrote that Grant “did not regret having made the assaults; he only regretted that they had failed.”
In the heat of the Mississippi summer sun, the dead men and horses began to putrefy. Grant did not want to ask for a truce to remove them, thinking that it was a show of weakness. More than one Confederate soldier wrote that the enemy was trying to stink them out of Vicksburg. Finally, after an appeal from Pemberton on May 25th, Grant allowed a 2 1/2 hour a truce and the Union army recovered its dead.
During the truce, men in blue and gray mingled between the lines. Observers wrote about “two Yanks and two Rebs” playing cards while other men swapped tobacco for coffee. Once the truce was over, everyone returned to their positions. The siege of Vicksburg began in earnest that day.
General Grant’s chief of staff, Lt. Col. John A. Rawlins issued Special Orders No. 140 for Grant: “Corps Commanders will immediately commence the work of reducing the enemy by regular approaches. It is desirable that no more loss of life shall be sustained in the reduction of Vicksburg, and the capture of the Garrison. Every advantage will be taken of the natural inequalities of the ground to gain positions from which to start mines, trenches, or advance batteries. …” Grant later wrote in his memoirs, “I now determined upon a regular siege—to ‘out-camp the enemy,’ as it were, and to incur no more losses.”
With this order, Union troops began to dig a series of fortifications and approaches to the Confederate defensive lines. As the siege progressed, “saps” or “approach trenches,” deep enough to conceal troops, zigzagged their way toward the works protecting Vicksburg.
Ten major approaches were carried forward by pick and shovel details, each with a network of parallels, bomb proofs, and artillery emplacements. Over 60,000 feet of trenches and 89 artillery positions, mounting 220 guns, were completed. This massive undertaking was placed under the supervision of Grant’s chief engineer, Captain Frederick E. Prime.
The Union forces had an almost limitless supply of ammunition for their sharpshooters and artillery. They were able to protect the work parties from Confederate sharpshooters as their comrades continued to advance against the enemy works.
Lt. Gen. John C. Pemberton was hoping that by continuing to hold this key bastion, he would give his superior, General Joseph E. Johnston the opportunity to relieve Vicksburg. With each passing day, the Confederate supply situation worsened. The Confederate commander considered it “a matter of vital importance that every charge of ammunition on hand should be hoarded with the most jealous care.”
He issued strict orders that both rifle and cannon should be fired only when absolutely necessary, preventing the Confederates from keeping up the steady fire needed to hold the Union siege activities in check.
Realizing that the Army of the Tennessee did not have sufficient troops to completely invest the 12 miles of enemy fortifications, Grant asked for reinforcements since there were still unguarded roads that led out of Vicksburg. Grant received relief from Maj. Gen. Henry Halleck in this regard.
On June 11, 1863, a 5,000 man division from the Department of the Missouri under Maj. Gen. Francis J. Herron arrived. Herron’s troops, remnants of the Army of the Frontier, were attached to McPherson’s corps and took up position on the far south.
The final force of reinforcements was the 8,000-man strong IX Corps from the Department of the Ohio, led by Maj. Gen. John G. Parke, arriving on June 14. With the arrival of Parke, Grant had 77,000 men around Vicksburg.
Grant still had the vexing problem of Maj. Gen. John A. McClernand. The relationship between Grant and McClernand had been a touchy one for some time. McClernand had tried to obtain an independent command for some time by using his political connections and appealing directly to President Lincoln and Secretary of War Edwin Stanton. His actions only exacerbated his relationship with Halleck and Grant.
After the failed assault of May 25th, Grant considered relieving McClernand because of his high casualty rate and his doubts about the accuracy of McClernand’s appeal for help. McClernand had sent Grant a message asking for reinforcements and saying that he was in control of both of his objectives. The reality was that he only possessed a part of one enemy position.
Grant hesitated to relieve him because McClernand was a capable officer who had generally performed ably. He was respected by his men and Grant did not wish to cause a loss of morale in the 13th Corps. Grant decided to retain McClernand for the rest of the siege and then ease him out of command.
McClernand was to solve Grant’s dilemma himself. Against standing orders from the War Department, McClernand had a bombastic letter published in a number of Midwestern newspaper that praised his corps at the expense of the Sherman and McPherson’s corps. His fellow corps commanders were incensed and demanded that Grant take action. On June 18th, Grant relieved McClernand for violating standing orders and replaced him with Maj. Gen. Edward O.C. Ord.
By June 22nd, Grant had become concerned about the forces of General Joseph E. Johnston who were in his rear to the east. He stationed one division in the vicinity of the Big Black River Bridge and another reconnoitered as far north as Mechanicsburg, both to act as a covering force.
When Parke’s Corps joined his command, Grant used them as the nucleus for a special task force to prevent Johnston, who was gathering troops at Canton, from interfering with the siege. He placed Maj. Gen. William T. Sherman in command of this force. Brig. Gen.Frederick Steele replaced him at the XV Corps. Johnston eventually began moving to relieve Pemberton and reached the Big Black River on July 1, but he delayed an attack against Sherman until it was too late for the Vicksburg garrison, and then fell back to Jackson.