Siege of Vicksburg

By Larry Holzwarth

The grand strategy under which the Union army conducted its military operations during the Civil War was called The Anaconda Plan. First proposed by General Winfield Scott, the plan specified gaining complete control of the Mississippi River. By the spring of 1863, only two Confederate strongholds along the river stood in the way: Port Hudson, Louisiana, and Vicksburg, Mississippi.

Situated on bluffs overlooking a horseshoe-shaped bend in the Mississippi River, the city of Vicksburg was vital to Confederate strategic interests. Control of the Mississippi prevented the isolation of the Confederate states west of its banks, and it prevented the Union from using the river as a highway to move troops and supplies into the deep south via the ports of New Orleans and Mobile. To prevent the river from becoming a Union-run waterway, the Confederates constructed strong defenses around Vicksburg.

The United States Navy under Admiral David Farragut twice attacked Vicksburg in the spring and early summer of 1862, attempting to bombard the city into submission. Failing at that, Farragut decided to bypass the bluffs on which Vicksburg and its fortifications were located by digging a canal across the De Soto Peninsula. Union Brigadier General Thomas Williams, who was attached to Farragut’s command and under orders from General Benjamin Butler, Union commander at New Orleans, began excavation of the canal in late June 1862. By the end of July, heat and diseases had rendered the effort unfeasible. The canal was abandoned and the Union troops and gunboats were withdrawn.

Map of canal

In the fall of 1862, General Henry Halleck, the Commander of the Western Theatre, was promoted to the command of all Union armies, prompting his departure to Washington. At the time, Ulysses S. Grant commanded the Union Army of the Tennessee. Union General John McClernand, a political general who had convinced Lincoln that he could capture Vicksburg via an overland march down the Mississippi and received authorization to make the attempt, began assembling forces in Memphis. Halleck, new to Washington and concerned about McClernand’s political ambitions, promoted Grant as his replacement to overall command of the Western Theatre, giving him authority over McClernand’s troops and creating a source of political intrigue which would continue throughout the campaign.

An attack on Vicksburg was planned and underway by the late fall of 1862. Grant moved his army south, using the Mississippi Central Railroad as the line of march for his 40,000 troops. He ordered General William Sherman to follow the Mississippi River with his 32,000 men. Grant established a forward supply base at Holly Springs, a town located in north central Mississippi not far from the Tennessee border. The base would provide logistical support for the two-pronged assault on Vicksburg. By late December, Sherman had pushed his lines through the swamps northeast of Vicksburg near the strongly defended Walnut Hills. After several failed attempts to flank these defenses, being blocked by the impassable terrain, Sherman launched a frontal assault on December 29th, which the Confederates repulsed at the Battle of Chickasaw Bayou. Simultaneously to Sherman’s advance, Confederate cavalry raids by Nathan Bedford Forrest’s troops destroyed the lines of communication between Grant and Sherman, as well as the supply base at Holly Springs. Having evaluated the strength of the Confederate defenses, the difficulty of moving troops through the swampy terrain, and with supplies low after Forrest’s raids, Grant abandoned the overland attack on Vicksburg.

In January 1863, McClernand arrived in Memphis and designated the troops under his command as the Union Army of the Mississippi. McClernand also ordered Sherman to attach his XV Corps to this army, orders which would irritate Grant but which Sherman, being junior to McClernand, had no choice but to comply with. Sherman suggested an operation to McClernand in which Sherman’s troops, supported by Navy gunboats under Admiral David Dixon Porter, would assault Fort Hindman, a Confederate defense outpost on the Arkansas River. This action, known as the Battle of Arkansas Post, was undertaken without notifying Grant. Although the action was successful, Union casualties were high and Grant resented the operation, as it did little to contribute to his campaign against Vicksburg. He did not admonish McClernand however, which contributed to McClernand’s belief that he was operating independently of Grant’s army, with his presidential authorization overriding the military chain-of-command.

With the main Confederate defenses directed towards the Mississippi River, Grant now began a series of operations intended to use the bayous and waterways, augmented with improvements if necessary, to move his troops into positions from which they could assault Vicksburg. In late January, Sherman’s troops, under Grant’s orders, began work to widen and deepen the canal which had been abandoned by Williams the preceding summer (Sherman opposed the plan, but again followed his orders). The effort now became known as Grant’s Canal, though Sherman referred to it as Butler’s Ditch, after General Butler who had ordered the initial effort. Poor engineering did not take into account the vagaries of the Mississippi during periods of winter floods. An unexpected series of floods in February collapsed some of the work and filled the canal with detritus sediment, driftwood, and other debris. Attempts to clear the canal using steam dredges were unsuccessful as the canal would again flood at random, based on the Mississippi’s tendencies to overflow its banks in winter. By March, the canal was again abandoned.

Remnants of Grant’s Canal

Another canal, northwest of Vicksburg, was successfully completed to Lake Providence, creating a water route to the Red River that would allow Grant to send troops to Port Hudson (just north of Baton Rouge, Louisiana). However, Grant did not have enough boats to ship a force large enough to have an impact, and the canal, the only effort which successfully skirted the Vicksburg defenses, was never used.

That winter other attempts to bypass Vicksburg’s guns via the water routes were attempted and failed. By late March 1863, Grant had made seven attempts to get at Vicksburg and experienced seven failures. In early spring, having found that the defenses northwest of the city were too strong to assault and the means of bypassing the city to the south and west too difficult to achieve due to the terrain, Grant developed a new strategy. He proposed to cross the Mississippi north of Vicksburg, march his troops past the city on the western side of the river, re-cross south of the city, and attack Vicksburg from the south and east. To accomplish this goal he reorganized the Army of the Tennessee, absorbing McClernand’s Army of the Mississippi and assigning McClernand to the command of the XV Corps. This unit was tasked with building a log corduroy road suitable for the Union troops to traverse the swamps to the river.

To get back across the Mississippi River once south of Vicksburg, Grant would need ships to transport his men. He asked Admiral Porter to run downriver with a fleet of ships, passing the gauntlet of Confederate artillery at Vicksburg. It could be a one way trip for Porter; the Mississippi’s strong current would make it impossible to return upstream in the face of the Confederate guns.

Grant began his move south on March 31, 1863, from Milliken’s Bend, a spot twenty miles northwest of Vicksburg. He had by now approximately 45,000 men under his command. McClernand’s troops had completed the seventy-plus mile road by the middle of April, and on the night of April 16th, Porter sent seven ironclad gunboats with attached coal barges and three troop transports floating silently down the Mississippi. However, the Confederates spotted them and opened fire from the bluffs at Vicksburg. One transport was disabled and left behind, but the rest made it past unscathed. So far everything was going as planned.

By April 28th, Grant’s army had reach Hard Times, Louisiana, a town on the Mississippi River just north of Grand Gulf, Mississippi. Grant’s initial plan was to cross the river at Grand Gulf, the site of a Confederate river fortress. To ensure that Confederate troops would not march south from Vicksburg to help defend Grand Gulf, Sherman was ordered to launch a diversionary attack on the defenses northwest of Vicksburg at Snyder’s bluff. Although repulsed in the three-day Battle of Snyder’s Bluff (April 29-May 1), Sherman was successful in keeping Confederate soldiers in Vicksburg.

On the morning of April 29th, the Union fleet of ironclads began a five hour bombardment of the Confederates at Grand Gulf, but could not defeat them. As a result, Grant decided to march even farther south. It would be at Bruinsburg, Mississippi, where he would finally cross the river. It would take two days (April 30th and May 1st) to get everyone onto Mississippi soil. Until the Normandy invasion on June 6, 1944, this operation would remain the largest amphibious landing by the United States Army.

By late afternoon on the 30th, 17,000 troops had been transported across the river. Grant decided to march towards Port Gibson during the night and take the Confederates by surprise. Around midnight, Union forces engaged Confederate pickets along the Rodney Road at the Shaifier House and fought until 3 AM. Throughout the night more and more Union soldiers who had landed at Bruinsburg arrived on the front lines. At dawn the men began a slow drive down Rodney and Bruinsburg Roads against the Confederates in what would be called the Battle of Port Gibson. Fighting raged throughout the day, with the Confederates constantly being driven back until they finally retreated around 5 PM.

Now in a position to begin his assault on Vicksburg, Grant was in receipt of orders directing him to first join General Nathaniel Banks in capturing Port Hudson. Grant sent a message to General Halleck in Washington, by courier, informing his superior of his intention to stick to his plans to take Vicksburg, contrary to his orders, knowing that it would take at least a week or more for Halleck to receive the message.

Grant next planned to strike the Southern Railroad of Mississippi somewhere between Vicksburg and Jackson, Mississippi, so that the supply line to Vicksburg would be cut. To do this he marched his army northeast towards Jackson. On May 12th, 3,000 Confederates near the town of Raymond, 14 miles southwest of Jackson, surprised the Union troops as they approached. Intelligence reports claimed the Union forces were small in number when in fact the first troops to be attacked, General James McPherson’s XVII Corps, numbered 10,000 strong, and more Union troops were on their way. By the end of the day the Confederates had been defeated once again. They withdrew towards Jackson, a move which allowed Grant to cut the railroad link to Vicksburg.

Confederate General John Pemberton meanwhile had sent messages to the Confederate War Department asking that troops from Robert E. Lee’s Army of Northern Virginia be dispatched to reinforce him. Lee, however, was by this time moving his army north on his invasion of Pennsylvania that would end in July at Gettysburg. The Confederates ordered General Joseph Johnston, then in Tennessee, to Mississippi to take command of that theater. Johnston arrived in Jackson on May 13th, one day after the Battle of Raymond.

Grant next decided to push on towards Jackson and take the capital city so he could destroy a rail and communication center. On May 14th, Johnston, under pressure from two Union Corps commanded by Sherman and McPherson, opted to abandon the city without much of a fight. A small force under the command of General John Gregg was ordered to engage Union troops just long enough for Johnston to get his men and supplies out of Jackson. At 2 PM the city had been evacuated and Gregg’s men began to withdraw as well. Grant had thus captured the capital of Mississippi with comparative ease and now directed his attention to Vicksburg.

Meanwhile, General Pemberton had been marching south from near Champion Hill, Mississippi, on his way to attack Union supply lines between Grand Gulf and Raymond when Johnston ordered him, for a second time, to attack Grant near Clinton. Pemberton turned around and returned to Champion Hill, and it was here on May 16th that his men attacked Grant’s army as it marched westward along the Southern Railroad of Mississippi towards Vicksburg. Grant counterattacked and the Confederates withdrew. Thus, by the 17th of May all Confederate units in the state were retreating towards Vicksburg.

When Pemberton’s troops reached the Big Black River bridge on May 17th, they turned one more time to face the Union pursuit. In the resulting Battle of Big Black River Bridge, the Confederates were again overwhelmed, fleeing the Union troops across two bridges, a railroad bridge and a steamboat mooring. Burning both bridges after crossing, the Confederates bought themselves enough time to enter Vicksburg that day.

Once Grant arrived outside of Vicksburg, he immediately sent out to capture the city, launching attacks on May 19th and 22nd to avoid a lengthy siege. The May 19th attack was made against the Stockade Redan, which guarded the Graveyard Road entrance into the city. The May 22nd attack was launched across a three mile front against all Confederate defenses from the Stockade Redan in the north to Fort Garrott in the south. Both attacks ended in failure and the Union sustained heavy casualties.

During the May 22nd assault, McClernand was ordered to capture positions on the Confederate right, including the Railroad Redoubt and the 2nd Texas Lunette, both of which, as well as other positions nearby, put up stiff resistance. McClernand asked for additional support from Grant, who at first refused, although after showing the note to Sherman he allowed Sherman, at his discretion, to move to support McClernand’s forces. Sherman launched a brief attack; appalled at the heavy losses and the impossibility of capturing the positions by direct assault, he withdrew his troops. This incident would later lead to McClernand issuing a self-congratulating message to his own troops which implied criticism of Grant, an act of insubordination that finally gave Grant reason to relieve the tiresome general of his command.

Not wanting to lose more lives in all out attacks against the well fortified Confederate defenses, Grant opted to lay siege to the city. Vicksburg was now surrounded, with Union ironclad gunboats blocking access via the river and Grant’s army preventing any connection with the outside world overland. Railroad access to the city was cut off and no additional supplies could be obtained. The siege of Vicksburg is generally regarded to have begun after the defeat of the Confederates at Big Black River Bridge and would continue for six weeks.

Siege warfare of the 19^th century consisted of constant bombardment of the besieged positions with heavy artillery, occasional sorties to capture the besieged outposts, movement of the artillery forward to the newly captured positions, and resumption of the bombardment, now from closer range. As the besieged resisted they became progressively weaker due to dwindling supplies, dropping morale, and the effects of the bombardment. Unless the siege could be broken by outside assistance, the besieged faced certain defeat.

With Pemberton under siege in Vicksburg, and fully aware of the strategic importance of retaining control over the city and denying Union access to the full Mississippi river, Confederate President Jefferson Davis ordered Major General Richard Taylor to attack Grant’s supply lines west of the river at Milliken’s Bend in Louisiana. Although Taylor objected to the attack, preferring to strike near New Orleans owing to the presence of more suitable terrain, he was overridden by his superiors. Taylor struck Union Colonel Herman Lieb’s troops, which included the African Brigade, in the pre-dawn hours of June 7th. Although the attack was initially successful, with the Union force withdrawing to the water’s edge, Union gunboats arrived on the scene to provide support and the Confederates soon withdrew without achieving their objective.

Grant noted in his memoirs that this was the first time “colored troops” had been under fire in a serious battle and commented that they had “behaved well.” The action at Milliken’s Bend has been cited as converting many Union generals to the advocating for additional African American units. More importantly to the Union army at the time was that the action prevented the disruption of Grant’s supply lines.

The constant bombardment of the Union Army using siege guns, Parrott guns, and mortars forced the citizens of Vicksburg to literally go underground, digging caves under the cliffs in an attempt to escape the constant pounding. More than 500 caves were dug into the cliffs. Many of these caves were furnished with furniture, rugs, and other comforts.

Although Pemberton was well equipped with ammunition, food and medicines were running short. The Confederate garrison continued to fire back at the Union positions, although somewhat ineffectively. Union gunboats pumped over 20,000 shells from howitzers and mortars, while Confederate guns on the bluffs above the river could not sufficiently respond.

Laying seige to the city and waiting for Pemberton to surrender did not mean that Union troops sat around doing nothing. The Union army had set up batteries opposite of all Confederate forts and proceeded to dig approach trenches towards them. The plan was to get close enough to then dig a mine under the fort, pack it gunpowder, and then detonate it with hopes of blowing a hole in the earthen walls so that Union soldiers could pour in and take control.

Most trench and mine projects were uncompleted at the time of the Confederate surrender, except at the Third Louisiana Redan. In late June, Union troops dug a mine under the redan (a triangular fort) and packed it with over a ton of black powder. After detonating the explosives on June 25th, the Union troops followed up with an infantry assault, which failed when the troops became effectively trapped in the crater. The men of the Third Louisiana Infantry Regiment responded with rifle fire and rolled artillery shells, short fused, into the crater. This scene would be repeated with similar grisly results later in the war during the siege of Richmond-Petersburg.

Grant had demanded unconditional surrender since the beginning of the siege, but in early July he relented, offering to parole the Confederates if they surrendered (parole was a gentleman’s agreement to return home and not to reenter the war). Pemberton accepted these terms on July 3rd, at about the same time Pickett’s Charge was being repelled at Gettysburg, Pennsylvania. The surrender was formalized the next day.

With Vicksburg’s fall to the Union, and Port Hudson’s surrender five days later, the interior rivers from Pittsburgh to New Orleans were in Union hands. Grant would be promoted to the Commander of all Union Armies in the aftermath of his victory. He would return to the east to make his headquarters with George Meade’s Army of the Potomac, the victor at Gettysburg.

Although less celebrated today than the simultaneous victory at Gettysburg, Vicksburg was the pivotal point in the Civil War. It removed the Mississippi from Confederate control, isolated the states west of the river from the rest of the south, and provided a blow to morale within the Confederacy. It also provided for future operations in the deep south, through the Tennessee Valley towards Atlanta, unhampered by concerns of actions on the right flanks of the Union troops.

The Vicksburg Campaign remains a model of joint military-naval operations in a harsh and unknown terrain. Grant’s success could not have been achieved without the co-operation and support of Admiral David Porter, a lesson Grant would remember during operations along the James River in Virginia in 1864-65.

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